Method, system and medium for assessing the impact of various ailments on health related quality of life

ABSTRACT

The present invention relates to a system and method for assessing the impact of an ailment on a health related quality of life domain of a patient using a standardized common metric. The standardized common metric of the present invention enables the impact of various ailments to be compared.

RELATED APPLICATION

The present application claims benefit of U.S. Provisional ApplicationNo. 60/662,060 filed Mar. 15, 2005, and the present application is acontinuation-in-part of U.S. application Ser. No. 09/873,500, filed Jun.4, 2001, which is a continuation in-part of U.S. Provisional ApplicationSer. No. 60/209,105 filed Jun. 2, 2000, which are all incorporated byreference in their entireties.

BACKGROUND OF THE INVENTION

The present invention relates to an assessment technique, which isconveniently practiced on a computer. The computer is either a ‘standalone’ or connected to a computer network, such as a local area network(LAN) or the world wide web, which is frequently and interchangeablyreferred to as the Internet. Other devices, including wireless enableddevices, may also be utilized in the assessment technique. Specifically,the present invention relates to a system, method and medium for theassessment of the impact of an ailment on a health related quality oflife domain of a patient, where a standardized common metric forcomparing the impact of various ailments is established.

In the United States alone, over 100 million people have chronic healthconditions, accounting for an estimated $700 billion in annual medicalcosts. In an effort to control these medical costs, many healthcareproviders have initiated outpatient or home healthcare programs fortheir patients. The potential benefits of these programs areparticularly great for chronically ill patients who must treat theirdiseases on a daily basis. However, the success of these programs isdependent upon the ability of the healthcare providers to monitor theirpatients remotely in order to avert medical problems before they becomecomplicated and costly.

Various surveys for assessing health and impact of a particular diseaseare available, but there is no standardized common metric for comparingthe impact of various ailments. Although the disease-specific tools,aimed at assessing the impact of a particular disease on HRQOL, havecertain sensitivity and specificity aspects, unfortunately they do notpossess the ability to compare results across diseases. This inabilitymakes it harder to build a body of results that could helpinterpretation of the meaning of specific scores.

SF-36 Health Survey—Manual & Interpretation Guide, written by John H.Ware, Jr., Ph.D. et al., and published by The Health Institute, NewEngland Medical Center, Boston, Mass. (copyright, 1993) describes aprotocol for an improved health assessment and evaluation technique. Theguide includes a thirty-six question survey, which is useful inassessing general health variables. Many have cited the thirty-sixquestion survey as providing excellent results notwithstanding itsbrevity as compared to other surveys.

“Dynamic Health Assessments: The Search for More Practical and MorePrecise Outcomes Measures” by John E. Ware, Jr., Jakob Bjorner and MarkKosinski, (inventors of the present application) published in theQuality of Life newsletter, No. 21 (January-April 1999) generallydiscusses a psychometric method for assessing indicia of ideal healthstatus.

An article related to the SF-36 survey is “The MOS 36-Item Short FormHealth Survey (SF-36)” by John H Ware Jr., PhD. and Cathy DonaldShelbourne, PhD, published in Medical Care, Vol. 30, No. 6, June 1992.

A further article related to certain computer testing algorithms isdescribed at pages 103-135 of Computer Adaptive Testing—A Primer byHoward Wainer, et al. published by Lawrence Erlbaum Associates,Hillsdale, N.J. 1990.

A further shortcoming in these surveys is that they are often directedtowards providing an objective evaluation of a patient and his/herhealth. This method of evaluation doesn't allow a patient to providetheir own feedback as to their own perceived state of health, which canbe a significant distinction. Although, the objective evaluation of thepatient and his/her health provides the healthcare practitioner orhealthcare provider with objective indicia as to the perceived state ofthe patient's health, it is not necessarily helpful in all instances tothe patient in understanding his/her health status or progress duringany particular time interval. That is, the objective survey results arenot frequently presented in a meaningful fashion to the patient. Rather,many of these surveys are primarily directed to the healthcare provideror healthcare organization. A subjective survey is much more meaningfulto the patient in understanding their own health status and progressover any time interval. Healthcare providers/healthcare organizations,however, rarely utilize such subjective surveys, and traditionally favorthe objective types of surveys known to the art.

Another shortcoming relating to the systems, methods, and surveys, whichare cited above, is the relevant inflexibility of the surveys, which areset out in a standardized form and need to be completed in total by thepatient/respondent every time that the survey is taken. Thus,patient/respondent encounters the same burden every time that he or sheresponds to such survey.

Furthermore, the prior art tests and surveys are non-adaptive. Priorsurvey results of a patient/respondent, or a group ofpatients/respondents, do not affect the future surveys that they aregiven. As such, the later surveys do not provide for differentiation inthe health status of a patient.

An additional problem in the prior art surveys is their inflexible modesof administration. The surveys generally consist of either thetraditional paper-based type or a computer-based replica of the same.The traditional paper-based versions provide a series of questions onpaper sheets or booklets for the patient/respondent. After thepatient/respondent completes the survey, the administrators evaluate theresponses. While cost effective, the format remains inflexible. In thecase of the computer-based surveys, many of the prior art surveys arelittle more than computer-driven versions of the same paper-basedsurveys, which provide little or nothing in added flexibility.

A further shortcoming in many of the prior art surveys is that they areunsuited for self-administration by a patient/respondent. In the contextof the objective surveys described above, the patient/respondent may bevery capable of taking the survey and responding to the questionsprovided therein, but many of these surveys do not provide an immediateresponse that is readily understood by the patient/respondent by theconclusion of the survey. Thus, while the “objective” type survey mayprovide meaningful results to a medical practitioner or a healthservices organization, it is not particularly adapted as aself-monitoring instrument to a patient or respondent.

Additionally, Related art includes tools for assessing Health RelatedQuality of Life (HRQOL) which have enabled researchers and clinicians tobetter understand the impact of disease from the patient's perspective(Ware J E, Jr. (2003). Conceptualization and measurement ofhealth-related quality of life: comments on an evolving field.Arch.Phys.Med.Rehabil., 84, S43- S51; and McHorney CA (1997). Generichealth measurement: past accomplishments and a measurement paradigm forthe 21st century. Ann Intern Med, 127, 743-750, which are incorporatedherein by reference in their entirety). Such understanding isparticularly important for the treatment of chronic diseases prevalentin the aging population. Evaluating the impact of disease on the HRQOLof the elderly person, for example, is a key element in treatmentevaluation, monitoring of patients and screening for potential problems.

Such evaluation of the impact of disease on HRQOL has been performedwith two distinct sets of questionnaires: generic and disease-specific.In general, disease-specific measures demonstrate greater sensitivity(Kantz M E, Harris W J, Levitsky K, Ware J E, Jr., & Davies A R (1992).Methods for assessing condition-specific and generic functional statusoutcomes after total knee replacement. Med Care, 30, MS240-MS252; andBombardier C, Melfi C A, Paul J, Green R, Hawker G, Wright J et al.(1995). Comparison of a generic and a disease-specific measure of painand physical function after knee replacement surgery. Med. Care, 33, AS131-AS 144, which are incorporated herein by reference in theirentirety) and specificity than generic measures (Kantz et al., 1992)while generic measures better capture the total burden of disease (WareJ E, Jr. (1995). The Status of Health Assessment 1994. Annu Rev PublicHealth, 16, 327-354, which is incorporated herein by reference in itsentirety; Bombardier et al., 1995). In the presence of comorbidconditions, generic measures reflect the combined effects of primary andcomorbid conditions, whereas disease-specific measures reflect mainlythe primary disease (Kantz et al., 1992). Further, genericquestionnaires can be used with different diseases and thus allowcomparison of disease burden across diseases. Thus, when assessingpatients the researcher or clinician needed to use both types ofquestionnaires or had to make a choice between the generalizability ofthe generic questionnaire and the sensitivity and specificity of thedisease-specific questionnaire.

Therefore, it is desirable to have a single assessment tool, and relatedmethod, that can assess the impact of various diseases on HRQOL. It isalso desirable to have a system which scores everyone on a standardmetric so that the results of various different diseases can becompared. Accordingly, there is a real and continued need in the art forimproved systems and methods for the monitoring and assessment of impactof various diseases on HRQOL.

It is appreciated that these are but representative of certain needs inthe art which various aspects of the present invention address andprovide.

OBJECTS AND SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide animproved system that overcomes the shortcomings of the prior art.Accordingly, the present invention provides a system for remotelymonitoring patients and for communicating the results of such monitoringto the patient and, optionally, to others.

It is an object of the invention to provide a new approach tostandardizing disease-specific assessments of HRQOL to achieve theadvantages of both generic questionnaires, which can be compared acrossdiseases and treatments, and disease-specific questionnaires, which havegreater sensitivity and specificity.

It is a further object of the invention to produce disease-specificimpact scores, which will be comparable on a standard common metricacross different diseases or age groups.

In accordance with an embodiment of the present invention, a system forassessing the impact of various ailments on a health related quality oflife (“HQROL”) domain of a patient comprises a testing module and anevaluation module. The HRQOL domain comprises a plurality of indicatorsof functional health and well being. The test module generates acustomized test having a plurality of questions for the patient todetermine the impact of the ailment on the HRQOL domain. Each questionincludes an indicator of functional health and well being as a result ofthe ailment. The indicator is stably scaled across ailments whose impactis to be assessed to establish a standardized common metric forcomparing the impact of various ailments. The evaluation moduleevaluates, after each question, answers provided by the patient toestimate an ailment impact score and a confidence level in the accuracyof the estimated score. The evaluation module controls the test moduleto dynamically modify the test if the estimated confidence level isoutside a pre-determined threshold.

In accordance with an embodiment of the present invention, the systemfor assessing the impact of various ailments on a HQROL domain of apatient as aforesaid, further comprises a standardization module forgenerating a standardized common metric of the impact of an ailment onthe HRQOL domain across a plurality of ailments or age groups.

In accordance with an embodiment of the present invention, thestandardization module of the system as aforesaid further comprises auni-dimentionality, differential item functioning, item bank andordering modules. The uni-dimensionality module performs auni-dimensionality evaluation on a plurality of indicators of functionalhealth and well-being impacted by the plurality of ailments to provide afirst set of candidate indicators. The differential item functioningmodule performs a differential item functioning analyses on theplurality of indicators of functional health and well-being impacted bythe plurality of ailments to provide a second set of candidateindicators. The item bank module builds an item bank of the plurality ofindicators of functional health and well-being impacted by the pluralityof ailments from the indicators that are members of both the first andsecond sets of candidate indicators to provide indicators that arestably scaled across the plurality of ailments or age groups. Lastly,the ordering module orders the indicators of functional health andwell-being impacted by the plurality of ailments that are stably scaledacross the plurality of ailments or age groups in accordance with therelative level of ailment impact defined by each to form a standardizedcommon metric of the impact of an ailment on the HRQOL domain of the atleast one patient across the plurality of ailments or age groups.

In accordance with an embodiment of the present invention, a method ofassessing the impact of an ailment on an HRQOL domain of a patientcomprises the steps of generating a customized test and evaluatinganswers to the customized test. The HRQOL domain comprises a pluralityof indicators of functional health and well being. The customized testhas a plurality of questions for the patient to determine the impact ofthe ailment on the HRQOL domain. Each question comprises an indicator offunctional health and well being as a result of the ailment. Theindicator is stably scaled across ailments whose impact is to beassessed to establish a standardized common metric for comparing theimpact of various ailments. After each question, answers provided by thepatient are evaluated to estimate an ailment impact score and aconfidence level in the accuracy of the estimated score; and dynamicallymodifying the test if said estimated confidence level is outside apre-determined threshold.

In accordance with an embodiment of the present invention, the method ofassessing the impact of an ailment on an HRQOL domain of a patient asaforesaid, further comprises the step of generating a standardizedcommon metric of the impact of an ailment on the HRQOL domain across aplurality of ailments or age groups.

In accordance with an embodiment of the present invention, the step ofgenerating a standardized common metric of the impact of an ailment onthe HRQOL domain across a plurality of ailments or age groups furthercomprises the steps of: performing a uni-dimensionality evaluation on aplurality of indicators of functional health and well-being impacted bythe plurality of ailments to provide a first set of candidateindicators; performing a differential item functioning analyses on theplurality of indicators of functional health and well-being impacted bythe plurality of ailments to provide a second set of candidateindicators; building an item bank of the plurality of indicators offunctional health and well-being impacted by the plurality of ailmentsfrom the indicators that are members of both the first and second setsof candidate indicators to provide indicators that are stably scaledacross the plurality of ailments or age groups; and ordering theindicators of functional health and well-being impacted by the pluralityof ailments that are stably scaled across the plurality of ailments orage groups in accordance with the relative level of ailment impactdefined by each to form a standardized common metric of the impact of anailment on the HRQOL domain of the at least one patient across theplurality of ailments or age groups.

In accordance with an embodiment of the present invention, a computerreadable medium comprises code for assessing the impact of an ailment onan HRQOL domain of a patient. The HRQOL domain comprises a plurality ofindicators of functional health and well being. The code comprisesinstructions for: generating a customized test having a plurality ofquestions for the patient to determine the impact of the ailment on theHRQOL domain, wherein each question includes an indicator of functionalhealth and well being as a result of the ailment, wherein the indicatoris stably scaled across ailments whose impact is to be assessed toestablish a standardized common metric for comparing the impact ofvarious ailments; evaluating, after each question, answers provided bythe patient to estimate an ailment impact score and a confidence levelin the accuracy of the estimated score; and dynamically modifying thetest if the estimated confidence level is outside a pre-determinedthreshold.

These and other objects and advantages will become more apparent afterconsideration of the ensuing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example, and notintended to limit the present invention solely thereto, will be bestunderstood in conjunction with the accompanying drawings in which:

FIG. 1 depicts a flowchart of a further aspect of the Assessment Method;

FIGS. 2A-2C depict a series of graphical representations of statisticalassessment of two questions and responses thereto as provided by a groupof respondents, as well as the graphical representations of a derivedstatistical assessment;

FIGS. 3A-3B depict a series of graphical representations of statisticalassessment of two questions and responses thereto as provided by a groupof respondents, as well as the graphical representations of a derivedstatistical assessment of the Assessment Method;

FIG. 4 depicts a continuum flowchart of a further aspect of theAssessment Method;

FIG. 5 depicts a flowchart of a further aspect of the Assessment Method;and

FIG. 6 depicts a flowchart of a further aspect of the Assessment Method.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The definitions of the following terms as used in the specification aregiven by way of example to illustrate the concepts being discussedherein, and not intended to limit the terms solely to these definitions.

“Ailment”—A patient's condition which impacts on a health relatedquality of life domain of the patient. By way of non-limiting examples,these can include various diseases and conditions such as headache,hernia, rhinitis, asthma, overweight, osteoarthritis, diabetes, chronicobstructive pulmonary disease, depression, congestive heart failure, andrheumatoid arthritis, and the like.

“Assessment Method”—The monitoring system being described herein.

“Test Subject”—The person taking the test. Such person may be referredto as a “subject respondent”, and when the test relates to healthrelated subject matter, may be referred to as the “patient”.

“Testlet”—One or more questions primarily directed to evaluating thestatus of a Test Subject relating to a domain.

“Test”—One or more testlets which are used to evaluate one or moredomains.

“Domain”—An aspect or condition experienced or perceived by the testsubject sought to be evaluated by a test or testlet. By way ofnon-limiting examples, these can include various health-related measuressuch as severity of headaches, level of depression, degree of personalmobility, self-perceived status, general well being, etc. Othernon-health related aspects or conditions perceived by a test subject mayalso be considered as valid domains as “customer satisfaction”, and thelike. By way of non-limiting examples, these also can include a healthrelated quality of life domain which can include: physical, social,role, emotional, and cognitive functioning, and the like.

“Test Session”—A single episode of the administration of a test.Frequently, a plurality of test sessions are used by the test subjectsregarding the test subject with regard to that test subject's perceptionof their personal condition or perceptions thereof relating to one ormore specific domains.

“Subject Group”—A set of one or more test subjects who are participatingin the Assessment Method in order to evaluate one or more domains whichare common to each of the test subjects making up the subject group. Thesubject group can be a single individual test subject, but usuallycomprise two or more test subjects. By way of example, the subject groupmay be one or more test subjects who are associated with each other dueto a common domain sought to be evaluated. The evaluation may relate tothe individual test subject as well as for the subject group. Examplesof such may include a group of headache sufferers, one or more personssuffering depression, and the like. A still further example of a subjectgroup may be one or more test subjects who are associated with eachother due to a common variable, and the desire to evaluate the responseselicited from a particular test subject as well as the whole subjectgroup related to the variable. By way of example, such a variable may bea pharmaceutical composition which is being administered to one or moreof the test subjects making up the subject group. In another example,the variable may be the practice of a specific therapeutic procedureupon one or more of the test subjects comprised in the subject group. Asa still further example, the subject group may be one or more testsubjects receiving specific health related services from a commonprovider, such as specific doctor, or a group of doctors, ororganization such as health maintenance organization (HMO),pharmaceutical company, etc.

“Survey Respondent”—A person participating in a survey used in the testgeneration process of the Assessment Method.

“Device”—An article, apparatus, or instrument capable of presentinginformation to a test subject relating to the Assessment Method, whichis desirably also capable of receiving a reply from the test subject. Byway of non-limiting example, exemplary test devices include stand-alonecomputers, one or more computers connected to a network, one or morecomputers connected to the Internet, a computer terminal or other devicethat may be provided in an information kiosk, Internet appliances,hand-held computers also frequently referred to as “portable digitalassistants” (PDA), Web-TV devices, telephones (both wired and wireless),bi-directional wireless communication devices such as bi-directionalpagers and the like, as well as paper forms. Ideally the devices aretwo-way communications devices, particularly devices which include adisplay means (such as a cathode ray tube, flat panel display, and thelike) or other means for prompting an input (such as audio devices,speech synthesizers, and the like) and an input device (such as buttons,keyboards, computer mice, touch pads or touch screens and the like.)

The present invention comprises several processes or modules, including,but not limited to, test generation, testing or administering,evaluating and reporting. These processes of the present invention aswell as others are described hereinafter.

In the test generation process or module, the system collects data froma pre-existing data pool or database of questions and answers,statistically assesses the data, and forms a test for subsequent use inthe testing process and process (or administration and evaluationmodules). In accordance with an embodiment of the present invention, thesystem collects data by generating a survey of questions with a list ofpossible answers and providing it to one or more survey respondents inorder to elicit their responses thereto. The individual questions of thesurvey should be similar to, or, preferably, the same as the tests to besubsequently utilized in testing and evaluation. Such similarity, oridentity, in questioning ensures a high degree of relevance andstatistical accuracy between the initial results garnered from thesurvey and the subsequent operation of the Assessment Method. The testquestions can be of any form, and essentially can be directed towardsany of a wide variety of subjects. Preferably, however, the surveyincludes one or more questions related to each of one or more domainswhich are sought to be evaluated by the Assessment Method. In accordancewith an embodiment of the present invention, the questions have agraduated scale of possible answers associated therewith. A question isassociated with scaled responses that have at least two possible answers(such as “yes” or “no”), and, preferably, have a graduated scale ofpotential responses (such as integer numbers within a range “1, 2, 3, 4,5”, or “very bad, bad, fair, good, or very good”). The reasoning behindthe preference for a larger number of possible answers is that aplurality of potential responses to any test question provides aresponse that is more precise than a simple “yes” or “no.” Where one ormore of the test questions, preferably a majority of the test questions,have graduated scales of potential responses associated therewith, theAssessment Method provides more accurate results.

The survey comprises one or more questions evaluating one or more of thedomains that are perceptible to the survey respondents. The possibilityof domains varies widely, and covers all subjects of interest in theAssessment Method. The scope of a domain varies from general areas ofinterest, such as general health as perceived by a subject respondent,to more specific areas of interest, such as personal mobility. In suchan example, personal mobility or depression may comprise a more narrowlytailored subset of the broad general health domain. Hence, a broaderdomain can comprise subsets corresponding to domains of narrower scope.

The generation of the form and content of the individual questions on asurvey may vary from survey to survey. However, known-art surveysprovide good guidance in fashioning useful survey questions and theassociated possible responses. Of course, these survey questions andtheir answers must be relevant to the domain sought to be evaluated.

It is appreciated that the survey can be administered according to theprior art procedures as long as the collected data is available forsubsequent statistical assessments. Naturally, selection of the surveyrespondents plays a key role in ensuring the accuracy of the survey.Preferably, the survey respondents should closely correlate to theexpected test subjects of the Assessment Method.

In an alternative to the data collection process or module as discussedherein, the actual generation and administration of a survey can beskipped when a data pool of existing survey test questions and answers,relevant to the domains sought to be evaluated in the Assessment Method,are already available. Accordingly, the pre-existing test questions andanswers can be utilized directly. However, the pre-existing surveyquestions and answers should be used only when they are relevant to thedomains at issue.

In accordance with another embodiment of the present invention, thesystem establishes threshold limits, the minimum statistical probabilitywhich are considered to be acceptable for the valuation of the conditionof a test respondent with respect to a particular score level and/or aparticular domain. These limits can be arbitrary or based on a body ofdata, such as the survey questions and responses. Preferably, thethreshold limit values determine the number of questions from a Testletto be provided to a test respondent. For example, where the limitingvalue for a particular Testlet is relatively low, i.e., 50% probability,then it may be sufficient to query the test subject with a relativelysmall number of questions from that Testlet. Based upon the responsesreceived from the test subject to each of the questions in the Testlet,the present system compares these responses against the statisticalassessments previously generated in order to determine the cumulativeprobability of the status of the test respondent with regard to thecondition being evaluated in the domain. When such a cumulativeprobability meets or exceeds the threshold limits, the testing from theTestlet is concluded. This process or module provides a means foroptimizing or limiting the number of questions which in turn also reducethe burden imposed on the test subject. Conversely, where a high degreeof statistical accuracy is desired with regard to analyzing the statusof a test subject with respect to a particular domain, then the presentsystem may need to use a larger number of questions from the Testletduring the test.

In accordance with a further embodiment of the present invention, thesystem includes the testing and processes for administration orevaluation modules. The questions of the test, which have been assembledin the test generation process or module, are presented to one or moretest respondents on a device. Examples of such devices have been brieflymentioned above, and will be discussed in more detail herein. The devicemust be capable of presenting these questions in a discernible form aswell as receiving the response to the particular question being elicitedfrom the test subject. Subsequent to the receipt of such a response, thesystem compares the response against the statistically assessedresponses to the same test question, which had been presented in thesurvey and/or presented to the test subject in one or more prior tests.The comparison includes an evaluation of the statistical probability ofthe appropriate assessment of the test subject within the domain beingevaluated. If this statistical probability equates to or exceeds thethreshold limits which have been previously assigned, then the Testletis concluded. Alternately, if this threshold value is not attained, thenthe present system presents another question from the Testlet to thetest subject. Again, the present system compares the response againstthe statistical assessment of the same (or similar) question from thetest survey and/or a prior test. Thereafter, the system performs astatistical assessment based on the current responses to the testquestions from the Testlet in order to determine the statisticalprobability associated with the combination of answers to the Testletquestions received thus far. This analysis may include the determinationof the likelihood of the responses to each question for persons at aspecific scaled value within the domain, as well as the statisticalprobability of combination of responses to these questions. Preferably,such statistical analysis of the combination of questions also includesthe likelihood of consistent responses, as well as the likelihood oferroneous responses. Based on the results from such statisticalanalysis, the present system tests the probabilities against thethreshold limit again, and if the value equates to or exceeds such athreshold limit, the Testlet is concluded. Otherwise the process repeatsitself until the Testlet concludes.

In an embodiment of the testing process or module of the presentinvention, the system can establish an increased level of accuracy aswell as inquiry towards one or more domains from a larger set ofdomains. For example, the system can establish a higher threshold limitto the domain of particular interest and/or diminish the threshold limitto the domains of lesser interest. In this way, the system streamlinesthe process by not requiring an unnecessary amount of additionalquestions for domains of reduced interest, while requiring a increasednumber of questions for a domain of particular interest. Such a processreduces the burden on the test subject without reducing the statisticalaccuracy of the Testlet.

In an embodiment of the present invention, the reporting process ormodule comprises the scoring and presentation of responses elicitedduring the testing process. According to one alternative, the systemimmediately presents the test subject with the results of one or more ofthe Testlets upon the conclusion of such Testlet. In anotheralternative, the system withholds the results until the conclusion ofthe test. The system can present these results in a simple form, such asa simple numerical readout, or in a graphical format such as curves,slopes, graphs, and the like. Preferably, the system presents theresults in context. For example, it will present the scored Testletresults with a comparison to the average responses from one or moreother test subjects who have taken the same Testlet. Such comparisonsare most relevant when the test subject belongs to a group. As a furtheralternative, the system presents the results in comparison withhistorical results. Such historical results include, but are not limitedto, the results from prior test sessions for the same Testlet by thesame subject, the results of Testlets from the test having just beenadministered as compared to the cumulative results and historicalvariations of a group of test subjects, the results of the Testletshaving just been administered as compared to both the results from priorart test sessions for the test subject, as well as the cumulative scoresof a group of test subjects over the same time interval. In this manner,the system can present the test subject with relative changes orprogress over a timed interval, such as a period of days, weeks, months,years, etc. The time intervals can vary and are not critical to theAssessment Method. Where, however, a regularly-timed interval ispreferred, then it is also preferred that the test sessions occurapproximately at the same corresponding timed intervals, i.e., monthly,weekly, daily, etc. In such a manner, uniform time intervals can beconveniently established. Such also facilitates monitoring of a testsubject.

A particular advantage of the Assessment Method as described herein isin that unlike many prior art surveys which are inflexible and static,the test method of the present invention is dynamic. What is to beunderstood by static is that a survey is repeated for each test sessionand there is no possibility of altering the number of questions relatingto a domain, or their sequence, or indeed the length of the survey. Ashas been noted above, such is particularly burdensome upon individuals,particularly where such individuals need to have the tests administeredseveral times, such as in regular periodic intervals. Burdensome surveysare known to be more prone to errors, including misunderstanding and/ormisanswered questions, as well as questions for which no responses havebeen provided. According to an aspect of the Assessment Method, duringthe administration of a test, based on the responses to questionselicited, the Assessment Method is capable of increasing or decreasingthe number of questions presented to the test subject. As has been notedabove, wherein a threshold limit has been established for a particularTestlet, then the Assessment Method need not present questions whichexceed the minimum number of questions required in order to satisfy thethreshold limit. The converse is also true, as wherein there may be adomain which is of particular interest or concern with respect to thetest subject, then the threshold limits may be established at anincreased level such that a larger number of questions from a Testletneed be presented prior to the conclusion of the Testlet directedtowards assessing the status of the test subject with regard to theircondition respective to a domain.

In accordance with an embodiment of the present invention, theAssessment Method establishes the test for one or more domains based onan increased level of accuracy as well as inquiry towards one or moredomains from a larger set of domains. This can be done, for example, byestablishing a higher threshold limit to the domain of particularinterest and/or diminishing the threshold limit to the domains which areof lesser interest. The overall benefit of this is that wherein a testis directed towards evaluating several domains relevant to the testsubject, then additional questions are not required for domains whichare of reduced interest, while increased number of questions related toa domain of particular interest can be provided during the test. Suchreduces the burden on the test subject without reducing the statisticalaccuracy of the Testlet.

A further embodiment of the evaluation or reporting process or module ofthe present invention comprises the provision for a method of estimating“skipped” answers to test questions. For example, when a test subjectomits the response to one or more questions, then, based on thestatistical analysis of the questions which have been properly respondedto, the system calculates an estimate of the likelihood of the subject'sresponse to the “skipped” question. More specifically, for a Testlethaving a plurality of questions, i.e., five questions, directed towardsevaluating a specific domain, but only four of the five questions havebeen responded to, a statistical analysis determines the correspondencebetween the four properly responded to questions and the fifth omittedquestion. If there is a sufficient level of consistency between theseanswers, namely a satisfactory degree of statistical probability thatthe answers to each of the four questions responded to correspond to aspecific value, or limited range of values represented by the ordinateaxis, then the system can provide a reasonable prediction that theskipped question would have been responded to with the availableresponse which corresponds to that same ordinate axis value, or ordinateaxis value range.

Further embodiments of the process or evaluation module of the presentinvention include the ability to utilize the results from the survey andparticularly from the test administered and the resultant scalesrepresentative of their condition with different scales taken fromdifferent tests. The system utilizes various psychometric evaluationsand scales to indicate the status of test subjects within certaindomains. Prior art system have not been able to accurately interrelateand provide a correlation between the scales of these differentpsychometric evaluation techniques. In this embodiment of the presentinvention, the system uses the results of the Assessment Method withdifferent scales and correlates between the scales utilized by differentfirst psychometric analysis techniques. For example, the system presentsa subject respondent with a plurality of questions in each Testlet. Thesystem scores the responses to questions relative to the scales of boththe first and second psychometric techniques. The system can establish asurvey for each of the techniques and score the results on both scalessimultaneously. At the conclusion of the test, and especially at theconclusion of a plurality of test sessions, the system can establish acorrelation between these varying scales based on a derivation from thestatistical analyses of consistent responses with respect to a subject'sperceived condition relative to a domain. This is an invaluable aid inadvancing psychometric analysis.

In an embodiment of the present invention, the system provides a furtheradvantage by allowing the patient to self-administer a test. In anotherembodiment of the present invention, the system provides yet a furtheradvantage through subject assessments of survey results. The systemallows the subjects of the test to assign subjective measures to theirresponses based upon the individual subjective assessment and evaluationof their condition with regard to a domain and the scale of that domain.The system accounts for variations in this subjective assignment ofvalues according to the domain, particularly when the initial surveyquestions and answers are statistically assessed and optionally, but inmany cases, normalized against the overall population of the testsubjects participating in the survey.

An advantage of the Assessment Method of the present invention relatesto the type of reporting information which is provided to the testsubject. As stated herein, many prior art surveys provide informationwhich is of an objective nature, as these are frequently based on theobjective observations of individuals observing the test subject. Theseare not necessarily based upon questions and responses elicited directlyfrom the test subject without the intervention of such an observer. Incontrast, the Assessment Method is based upon the subjectivemeasurements which are assigned by the test subjects themselves whoparticipate in the Assessment Method. These are believed to beparticularly accurate as they are not based upon an external, imposedscale of a condition regarding a particular domain being evaluated, butare based upon the individual subjective assessment and evaluation oftheir condition with regard to a domain based on the scale of thedomain. Variation in this subjective assignment of values according to adomain are accounted for in the Assessment Method, particularly when theinitial survey questions and answers are statistically assessed andoptionally, but in many cases, normalized against the overall populationof the test subjects participating in the survey.

A still further important feature of the Assessment Method lies in thepresentation of the Testlet scoring results. As has been discussedabove, the data collected from test subjects is based on subjectivedata, i.e., their own perceptions and not based upon the perceptions ofothers viewing a test subject. According to particularly preferredembodiments, the information provided in the output of a report ispresented in a fashion which is particularly meaningful to the testsubject. This includes the forms and reports noted herein, such as thoseproviding a historical assessment of the progress of a test subject withregard to one or more domains; a historical progress of the test subjectwith regard to one or more domains as against the historical progress ofthe subject group; and test score results from a particular test ascompared to the test score results of prior test subjects havingparticipated in the Assessment Method, being those participating in thesurvey, those participating in prior test sessions, or any combinationof both of these groups. It is also foreseen that the content ofinformation and/or format of the report can be established by the testsubject, or by other individuals who may be participants or healthcareprovider. It is appreciated that such modification permits for a widedegree of modification and contemplates the generation of customizablereports, and the ability to modify the report at any time by the testsubject or other individuals. This provides a degree of flexibility toindividuals who may be participating or monitoring the tests.

The Assessment Method described herein can be used over a broad range ofsubject matter.

Personal health monitoring is an area which is particularlyadvantageously practiced utilizing the Assessment Method describedherein. Personal health monitoring can be used by test subjects toevaluate their own perceived condition relating to one or more domainsrelating to various aspects related to physical and/or emotional health.By way of non-limiting example, such domains include the impact ofheadaches, physical fitness, emotional fitness, depression, the impactsof asthma, as well as others not particularly elucidated here. One ormore of these domains may be evaluated by the administration of Testletshaving questions corresponding to each or one or more of the domains, orin the alternative, only a single domain, and a corresponding Testletcan be administered. While the test can be administered once, therebythe test subject can obtain a general measure of their responsesrelative to a larger population (such as of survey respondents and/orother test subjects), in an advantageous variation, the AssessmentMethod collects and stores the results of individual test sessions forthe test subject. The test subject, upon repeating the test, may, over aperiod of time, perform several test sessions which can be used toassess the changes in the perceived status of the test subject withregard to these domains. As is noted above, this information can begraphically provided to the test subject. Further, it is contemplatedthat this information related to a test subject is maintained by theAssessment Method in a “health notebook”. Such a health notebook is avisual representation of the collection of data relating to the testsubject's responses to test questions which have been obtained, andanalyzed during one or more test sessions. Such a health notebook isconveniently readily accessible from a device, and the results of thecontents of the health notebook are readily printable for review andstorage by the test subject apart from the device.

In accordance with an embodiment of the present invention, theAssessment Method or system assess the health status of a patient byproviding a customized test that dynamically changes based on thepatient's responses to the questions. The test module or processinitially estimates a score, e.g., 50%, and generates a customized testhaving a number of questions relating to a health domain to be assessed.The health domain relates to a condition experienced or perceived by thepatient, including but not limited to, severity of headaches, level ofdepression, degree of personal mobility, self-perceived status,effectiveness of a treatment, and general overall health. In accordancewith an aspect of the present invention, the Assessment Method andsystem can be also utilized to assess non-health related conditions,such as, job satisfaction, opinion polling, personality test, customersatisfaction, human relationship, and the like. The administrationmodule or process presents one question at a time to the patient. Aftereach question, preferably after the patient's response to the question,the evaluation module or process calculates or re-estimates the scoreand a confidence level in the accuracy of the estimated score. Theevaluation module or process estimates the score based on the variousstatistical analyses of the responses received from test subjects orother patients. Depending on the health domain, the evaluation modulesets a pre-determined threshold based on the patient's estimated score.The evaluation module or process dynamically modifies the test until theestimated confidence level is within the pre-determined threshold. Thatis, if the evaluation module or process determines that it can estimatethe patient's answers to the questions in the test, it terminates thetest since it has enough information to assess the patient's healthstatus. This advantageously reduces the burden on the patient, since anassessment can be made without the patient answering all of thequestions of the test or survey.

If the estimated confidence level is outside the pre-determinedthreshold, the evaluation module ranks the questions based on theestimated score and selects one of the questions that has not beenadministered or provided to the patient. Preferably, the evaluationmodule selects the question with the highest rank that has not beenpreviously administered to the patient.

A further aspect of the present invention relates to an apparatus forperforming the Assessment Method. This apparatus may be speciallyconstructed for the operation of the Assessment Method, or it maycomprise a general purpose computer as selectively activated orreconfigured by a computer program stored in the computer. Variousgeneral purpose machines may be used with programs written in accordancewith the teachings herein. It is also possible that it may in certaininstances be advantageous to construct more specialized apparatus toperform the required steps of the Assessment Method. Non-limitingexamples of such machines include the devices described previously, aswell as further machines and systems of machines described hereinafter.These non-limiting examples include stand alone computer, or connectedto a two or more computers on a computer network, such as a local areanetwork (LAN) as well as larger networks such as the Internet.

In one aspect of the present invention there is provided an assessmentand monitoring system which comprises a host computer facilitysupporting wired or wireless network delivery of user-relevantcomponents, such as tests, and output such as reports of the AssessmentMethod to multiple remote user interface devices.

In another aspect of the invention there is provided an assessment andmonitoring system which comprises a programmed general purpose computerwhich is programmed to operate the Assessment Method.

In another aspect of the invention there is provided an assessment andmonitoring system which comprises computer-readable media which containsthe instructions for use by a programmable general purpose computernecessary to operate the Assessment Method.

In another aspect of the invention there is provided an assessment andmonitoring system which comprises one or more devices which areconnected to a host computer facility which is programmed to operate theAssessment Method. The devices include without limitation computerterminals, general computers connected to the host computer facility,wireless devices including wireless telephones, two-way communicationsdevices, or other devices which include an display means (such as acathode ray tube, flat panel display, and the like) or other means forprompting for an input (such as audio devices, speech synthesizers, andthe like) and an input device (such as buttons, keyboards, computermice, touch pads or touch screens and the like.)

The Assessment Method according to the invention is conveniently adaptedfor implementation on physically compact, portable, user-interfacedevices such as small portable personal computers, and particularly handheld devices known as personal digital assistants. Those skilled in theart will understand that the system can readily be used on or adapted toother hardware platforms, for example, a desktop computer and can beexpressed in different software interfaces from that shown in thisspecification, especially ones that use different input devices such askeyboards, touch pads or touch screens and the like.

The Assessment Method can be implemented in software, and can beprovided for use for single-user operation on a stand-alone personalcomputer, or for multi-user operation on a network for use by a numberof test subjects. Particularly useful are embodiments wherein a testsubject is remotely administered a test session on a device, and thedevice is in communication with a host computer via a bi-directionalwired or wireless connection. Examples of the former may include localarea networks (LAN), wide area networks (WAN) as well as the Internet.Examples of the latter include connections wherein wireless means suchas transmission via IR signals, microwave or radio-frequencycommunications are employed for at least part of the communications pathbetween a device and the host computer. Thus a preferred embodiment ofthe invention comprises a host computer facility supporting wired orwireless network delivery of the tests and test sessions, as well asrelated information such as reports and the like, to multiple remoteuser interface devices. Such an embodiment is further preferred as ahost computer facility can be conveniently used for the administrationof tests in test sessions, statistical assessment of informationregarding tests and test sessions, as well as related functions. Onesuch function is operating as a central repository for maintainingrecords relating to test sessions, the identity of test subjects andsubject groups. A further such function is operating as a centraladministration center wherein changes or modification to the content ofthe Assessment Method, particularly changes to the questions and formatof the test and Testlets can be made.

The host computer facility provides data, or access to data, dataprocessing and communications resources for test subjects operating thedevices. The host computer facility can be a server or cluster ofservers with associated data storage volumes, and at least oneintelligent client providing access to the server or servers. The hostcomputer facility can call upon a variety of external resources andfunctions as a marshalling and processing center for organizingresources for utilization by limited capacity devices. In a preferredembodiment it is a co-ordination point on a network for a device used inthe administration of the Assessment Method. Optionally, the networkaccesses or includes a number of remote database sources providingaccess to elements both within and without the host computer facility.

The format of the test, test questions and reports may vary widely butdesirably are arranged to provide a readily understandable presentationof information on the device upon which the test is administered.Desirably such a format for such information is provided on screens in auser-friendly format, and provides a user-friendly interface forpresenting information and for providing a response to questions.Elements of such user-friendly interfaces are familiar to many computerusers, such as activatable buttons, pointers, scroll bars, icons, arrowkey, drop-down menus, windows and other screen symbols designed foractuation by a pointing device, for example, a mouse or trackball. Morepreferably, for embodiments implemented on a handholdabe computer, thepointing device is a pen or stylus. The Assessment Method itself can beprogrammed for operation in any suitable computer language (i.e.,Pascal, C/C+/C++, assembly language, BASIC, etc.) and on any suitableoperating system (i.e., UNIX, LINUX, Microsoft WINDOWS, Macintosh OS,etc.).

A further example of devices which find use with the instant inventionare small handholdabe computers (sometimes referred to as “personaldigital assistants” as well as “PDA”s). An example is the Pilot®Vhandheld computer vended by Palm Inc. and the Visor® handheld computersvended by Handspring Inc., as well as the Hewlett-Packard Jornada®handheld computers. These handheld computers include a central processorunit, programmable memory, a display/input means, and a means forcommunicating with a computer or computer network. These latter meansinclude a “wired” connection to a computer or computer network, as wellas “wireless” communications capabilities such as radio wave or infraredwireless communications means enabling them to exchange data with acomputer or computer network without the cost or inconvenience of hardwiring.

Pursuant to certain user-adaptive aspects of this invention, the screensare readily adapted to the test subject. This adaptive characteristic isa valuable benefit as the small and portable nature of the PDAsintroduce great convenience in the administration of a test session, andthe simplicity of interacting with such devices and providing responsesto questions presented on the screens facilitate compliance with aperiodic schedule of test sessions. The ease of use and suitability ofthe Assessment Method to such keyless or minimally keyed platforms,especially PDA's, is promoted by minimizing the need for actual text ordata entry by the user and by emphasizing instead data selection byselection from among possible responses to questions. Preferredembodiments of the invention allow quick pen selection of data itemsthrough columnar “pick lists” of possible responses.

A further example of an interactive interface and delivery systemsuitable for use as a device for administration of the Assessment Methodis a wireless telephone. A wireless telephone is suitable for use as adevice as it provides bi-directional communication capabilities with ahost computer or other computer, a keyboard or microphone suited forproviding an input indicating selection of a response to a question, anda screen or speaker which can be used to provide questions to a testrespondent in an audially and/or visually perceptible manner. Wirelesstelephones are also compact and portable and offer conveniences andbenefits similar to PDA's discussed above.

A further example of an interactive interface and delivery systemsuitable for use as a device for administration of the Assessment Methodmay be an ‘information kiosk’.

Such an information kiosk includes a touch-sensitive display, keyboardor other input means so that the test subject may respond to questionsprovided during the test. In other operational respects such aninformation kiosk is similar to a conventional computer workingindependently of a network, or similar to a computer terminal orcomputer attached to a network but is available in public spaces and areintended for public access. Such might be also viewed as a ‘publiccomputer’ or ‘public computer terminal.’ The benefits of such aninformation kiosk is that the test respondent need not be provided witha device in order to participate in the Assessment Method, but mayparticipate from an information kiosk. Such lowers the overall costswhich might otherwise be associated with the necessity of providingdevices to test subjects, particularly where a larger number of testsubject comprise a subject group. Further the public availability ofsuch information kiosks may ensure better compliance with any regimenfor which the Assessment Method may be utilized.

The present invention also comprises an approach to assessment ofdisease impact that combines the advantages of generic anddisease-specific questionnaires. This approach builds on a conceptualframework for the relation between clinical parameters, specificsymptoms, and disease impact and on a statistical model for the combinedeffect of question type and disease condition. Specifically, thisapproach builds on: (1) an item bank representing the most frequentlymeasured domains of disease impact (e.g., role functioning, socialfunctioning, physical functioning, and psychological distress),standardized across diseases, and (2) instructions to assess the impactof a specific disease (e.g., arthritis, diabetes) in answering eachquestionnaire item.

This model extends the psychometric Item Response Theory (IRT) models,which have been used in educational testing (Thissen D & Wainer H(2001). Test Scoring. Mahwah: Lawrence Earlbaum Ass, which isincorporated herein by reference in its entirety) and in health outcomesresearch (Ware J E, Jr. (2002). Conceptualization and Measurement ofHealth-Related Quality of Life: Comments on an Evolving Field. Arch PhysMed Rehabil, 83 (Suppl 2), S1-S9, which is incorporated herein byreference in its entirety). The IRT model and computerized adaptivetesting (CAT) are used to deliver a dynamic assessment of disease impactthat has far more precision for a given test length than a traditionalquestionnaire. This method allows a unified approach to thedisease-specific assessment of disease impact and comparison of impactacross diseases. This method also uses IRT and CAT software to yieldmore practical and precise assessments over a wide range of diseaseconditions and severity levels—eliminating “ceiling” and “floor”effects.

In accordance with an embodiment of the invention, CAT software can beprogrammed to select and administer the most informative and relevantdisease impact questions for each patient, with consideration of theclinical application. Standardization of the content of disease-specificimpact items and calibration of these items across diseases makes itpossible to achieve more responsive outcomes measures, while enablingmeaningful comparisons across diseases/treatments. Previous work hasused IRT methodology to develop a bank of items with equivalent itemcalibrations across five diseases. The aims of the present invention areto analyze existing data sets to evaluate the equivalence of these itemcalibrations across age groups and to test the feasibility of theDisease Impact CAT approach for elderly patients in a clinical setting.In accordance with an embodiment of the invention a Disease Impact CATcan be used to collect data from 100 middle aged and elderly patientswithin five groups: arthritis, depression, chronic obstructive pulmonarydisease, diabetes, and osteoporosis. Separate feedback reports can bedeveloped for the patients and the clinicians. Feasibility can beevaluated in terms of respondent burden, range of levels measured, itemusage, and response consistency, as well as the clinicians' andpatients' experience using the CAT tool of the present invention and thefeedback reports. In accordance with an embodiment of the invention, theproduct of the invention can be a Disease Impact CAT with evidenceregarding feasibility and acceptance. In accordance with an embodimentof the invention, a comprehensive Disease Impact CAT Assessment System,standardized across primary and comorbid chronic diseases/conditions, interms of psychometric performance and usefulness in clinical researchand practice can be developed.

A psychometric evaluation of the viability of the present approach wasperformed among adults in six disease groups: headache, asthma,rhinitis, osteoarthritis, rheumatoid arthritis, and congestive heartfailure (see e.g., Bjorner J B, Kosinski M, & Ware J E, Jr. (2003a).Calibration of an item pool for assessing the burden of headaches: anapplication of item response theory to the headache impact test (HIT).Qual Life Res, 12, 913-933; and Kosinski, M., Bjorner, J. B., Ware, J.E., Jr., Strauss, W., & Sullivan, E. Applications of ComputerizedAdaptive Testing to the Assessment of Osteoarthritis Impact (submitted).J Clin.Epidemiol, (in press), which are incorporated herein by referencein their entirety). One of the purposes of the present invention is toevaluate the generalizability across age groups of an embodiment of thepresent invention's approach to disease impact assessment and thefeasibility of applying the present invention's approach in clinicalpractice by:

-   a. Analyzing existing data sets to evaluate the equivalence of item    calibrations across age groups and to develop clinical benchmarks    for interpretation of disease impact scores;-   b. Developing a CAT of disease impact;-   c. Developing feedback reports for the patient and for the    clinician. The reports can contain guidelines for interpreting    patient scores;-   d. Testing the feasibility of the CAT among middle aged and elderly    patients with five specific conditions: Osteoarthritis, Depression,    Chronic Obstructive Pulmonary Disease, Diabetes, and Osteoporosis.    The evaluation can be based on:    -   1) Respondent burden, range of levels measured, floor and        ceiling effects, and item usage;    -   2) A psychometric evaluation of whether each patient's pattern        of responses is consistent with the hypothesized IRT model;    -   3) The patients' evaluation of the assessment situation and the        usefulness of the patient feedback report;    -   4) The clinicians' evaluation of the usefulness of the clinician        feedback report.

The present invention uses available data to evaluate whether thedisease impact approach disclosed herein is psychometricallygeneralizable across age groups (i.e., whether the item calibrations arestable over age). Data (n=100) can also be collected to assess thefeasibility of the approach of an embodiment of the present inventionamong elderly compared to middle aged patients in a primary caresetting.

An embodiment of the present invention can be a comprehensive diseaseimpact CAT, with preliminary evidence regarding feasibility,acceptability and empirical performance. In accordance with anembodiment of the invention the comprehensive disease impact CAT can bea fully functional CAT including a plurality of diseases for whichimpact can be assessed.

The basic notion of an adaptive test is to mimic what an experiencedclinician would do while assessing a patient. A clinician learns mostwhen he/she directs questions at the individual's approximate level ofhealth and functioning. Administering items that are either too easy ortoo hard provides little information. CAT employs a simple form ofartificial intelligence that selects questions tailored to thetest-taker, shortens or lengthens the test to achieve the desiredprecision, scores everyone on a standard metric so that results can becompared, and displays results instantly (Wainer H, Dorans N J, EignorD, Flaugher R, Green B F, Mislevy R J et al. (2000). ComputerizedAdaptive Testing: A primer. (2 ed.) Mahwah, N J: Lawrence ErlbaumAssociates, which is incorporated herein by reference in its entirety).Each test administration is adapted to the unique level of impact foreach respondent. For example, an adult who is able to “walk 50 feet” isnot asked to respond to a question about “walking 10 feet.” In practice,this approach minimizes the number of items that are administered to anindividual to obtain an estimate of the level of disease impact he/sheexperiences. The adaptive software of an embodiment of the presentinvention first asks a question in the middle of the range of impact,and then directs questions to an appropriate level based on theindividual's responses without asking unnecessary questions. On thebasis of the response to the first item, a score and confidence intervalare estimated, then the next optimal item is presented and a response isrecorded (see FIG. 6, which illustrates the logic of computerizedadaptive testing of an embodiment of the present invention). Withadministration of the next item, the score is re-estimated along with aunique confidence interval. The computer algorithm determines whetherthe stopping rule has been satisfied. If satisfied, the assessment ofthat concept ends. If not satisfied, new items are administered in aniterative fashion until the stopping rule is satisfied. By altering thestopping rule, it becomes possible to match the level of score precisionto the specific purpose of measurement for each individual. For example,more precision in scoring can be needed to monitor individual progressthan to identify presence of disease impact for an individualrespondent.

The psychometric methods of an embodiment of the present invention thatmake it possible to calibrate questionnaire items on a standard metric(“ruler”) also yield the algorithms necessary to run the “engine” thatpowers CAT assessments. These statistical models tell us how likely aperson at each level of function is to be described with each responseto each survey question. This logic is reversed to estimate theprobability of each impact score from a particular pattern of itemresponses. The resulting likelihood function makes it possible toestimate each person's score, along with a person-specific confidenceinterval. In principle, an unbiased estimate of disease impact (i.e., anestimate without systematic error) from any subset of items that fitsthe model is attained. The number of items administered can be increasedto achieve the desired level of precision. Features of the software ofan embodiment of the present invention that make it particularlysuitable for the research include options for setting stopping rules onthe basis of: (a) the accuracy of the score estimate (e.g., confidenceinterval<preset value), (b) maximum number of items (e.g., five orfewer), (c) a set number of items (e.g., most accurate estimate possiblewith 5 items), or (d) in terms of whether the probability of being aboveor below a pre-set score cut-off meets a particular criterion value(e.g., positive screen for substantial disease impact). Further, thecriterion for each of these stopping rules can be set to vary accordingto score level. The likelihood function can also be used for purposes ofmonitoring the quality of data for each respondent and for estimatingscores even if some responses are missing.

The market for a disease impact assessment system of the presentinvention that is comprehensive and precise and practical issubstantial. Current disease-specific assessment tools are typicallydirected at the severe end of the disease spectrum and do not permitcomparison of impact across diseases. Better tools are needed forclinical research evaluating new treatment options. To meet the needs ofdisease management, the challenge is even greater. Assessment tools thatmeet clinical standards of precision at the individual patient level arerequired. Current tools rarely meet these standards. By developing alarge bank of items on disease impact and calibrating them on a commonmetric, an embodiment of the present invention is able to provide aprecise assessment of disease impact. A traditional static survey usingthis item bank would, for many patients, require a half-hour tocomplete. Fortunately, this breakthrough in measurement can be the basisof a very efficient and successful commercial product using computerizedadaptive testing (CAT) software of an embodiment of the presentinvention. The result is very brief assessments that meet clinicalstandards of precision over a very wide range of scores, whilesubstantially reducing respondent burden and data collection costs. Theviability of this concept has been proven for assessment of headacheimpact using the software of an embodiment of the present invention.During a free public offering of CAT assessments of headache impactusing the software of an embodiment of the present invention and theinitial HIT item pool, the number of “hits” on www.amIhealthy.comincreased from 2,000 per day to more than 1.2 million per day with noincrease in costs.

Among the many lessons from that experience and follow-up studies ofpatients and caregivers (Ware J E, Jr., Kosinski M, Bjorner J B, BaylissM S, Batenhorst A, Dahlof C G et al. (2003). Applications ofcomputerized adaptive testing (CAT) to the assessment of headacheimpact. Qual Life Res, 12, 935-952; and Bayliss M S, Dewey J E, DunlapI, Batenhorst A S, Cady R, Diamond M L et al. (2003). A study of thefeasibility of Internet administration of a computerized health survey:the headache impact test (HIT). Qual.Life Res, 12, 953-961, which areincorporated herein by reference in their entirety), the importance of avery user-friendly front end that allows for true integration withclinical practice or disease management services and very short anduser-friendly patient and caregiver reports including simpleinterpretation guidelines was shown. Simple improvements made to thefirst page reduced “dropout” rates more than 50%. It is not enough tooffer the best possible disease impact measurement. Thus, customizedfront end presentations and very efficient feedback reports are acrucial part of the software and services package of an embodiment ofthe present invention for monitoring disease impact.

Standardization, which can lead to the widespread adoption of conceptsand measures, is another key element of an embodiment of the presentinvention. The development and inner-workings of the present invention'sstandards are documented thoroughly in user's manuals and reportsummaries in the peer-reviewed literature. The policies of the presentinvention provide for royalty-free access to the tools of the presentinvention for academic/scholarly research (leading to more than 4,000SF-36 publications to date) and require that commercial users pay aroyalty which is used to support research and development, and alsoprovides a return on investments. A comprehensive and efficient diseaseimpact assessment system of an embodiment of the present invention withestablished guidelines for its use in patient screening andinterpretation guidelines for use in outcomes monitoring can be verysuccessful in the health care marketplace.

Another key aspect of the strategy of an embodiment of the presentinvention is the expansion and evaluation of the Disease Impact CAT ofthe present invention for a number of additional diseases. Thisevaluation can partly be based on CAT only and partly be based onfielding the total item bank with new disease conditions to furtherevaluate the stability of item scaling across diseases. The advances inconnectivity provide efficient, effective means for administering suchtools in office-practice settings, in patients' homes and in numerousother settings.

The societal benefit that comes from improving the treatment ofdisabling conditions is unequivocal. The commercial opportunities thatexist are also quite clear and quite broad. Potential purchasers of theassessment system of an embodiment of the present invention includeprovider groups, insurers, disease management companies and employers. Asignificant advantage of the present invention is that the assessmenttools can be provided to such clients at a very small administration feeper individual. The CAT system of an embodiment of the present inventioncan be delivered through the Internet, as a stand-alone application onlaptop or desktop computers, or as a computer-assisted interview.

An embodiment of the present invention combines the advantages ofgeneric questionnaires (e.g., the SF-36), which can be compared acrossdiseases and treatments, and the greater sensitivity and specificity ofdisease-specific questionnaires. By greatly lowering data collectioncosts, reducing respondent burden, eliminating “ceiling” and “floor”effects and increasing the precision of individual patient scores,routine monitoring of HRQOL can become feasible as a clinical tool.Making repeated and individualized patient reports available to patientsand to caregivers in real time can radically improve both the processesof care and the very understanding of the nature of disease impact.

An embodiment of the present invention uses CAT to achieve abreakthrough in the information readily available for improving qualityof care and research on chronic diseases. It can do so by informinghistory-taking with psychometric science, adding rigor to patientassessment at the clinics and offices where patients receive their careand, via the Internet, in patients' homes. These techniques can improvethe precision with which nurses, social workers, physicians and otherstaff record patients' functioning and well-being, allowing for bettercare and clinical research, and the information can be integrated into acomplete electronic medical record, promoting comprehensive patientcare.

The concept of disease impact presented herein has important connectionsto the concept of participation, proposed by the WHO and defined as“involvement in a life situation” (World Health Organization (2001).ICF: International Classification of Functioning, Disability, andHealth. Geneva: WHO, which is incorporated herein by reference in itsentirety). Previous attempts to measure this social dimension of healthas a generic term did encounter problems, since operationalization of“social well-being” (World Health Organization (1948). World HealthOrganization constitution. In Basic Documents (Geneva: WHO, which isincorporated herein by reference in its entirety) was affected by manynon-health factors and not strongly associated with the person's ownglobal health assessments (Ware, Jr., 1995). However, the assessment ofthe impact of a specific disease of an embodiment of the presentinvention on a range of “life situations” seems to overcome theseproblems.

The analyses presented herein are also important because they canspecifically address the question of comparability of results across agegroups and the applicability of the CAT approach among the elderly.Psychometric tests of an embodiment of the present invention can be usedto assess whether the concept of impact is stable across age groups.Since concepts like impact and participation (see above) involve socialand role functions, it is possible that the meaning of impact changeswith age. Modem psychometrics discussed herein provide strong tools forthe evaluation of such effects and, if found, the ability to correct forthese changes to ensure comparable measurement across age groups (see,e.g., Bjorner J B & Kristensen T S (1999). Multi-item scales formeasuring global self-rated health. Investigation of construct validityusing structural equations models. Research on Aging, 21, 417-439, whichis incorporated herein by reference in its entirety). Testing can beused to evaluate whether a CAT approach is acceptable to elderlypatients and how a CAT can be designed to maximize acceptability. Inrecent strategy documents from the NIH, the use of CAT has been promotedas a technique that potentially could revolutionize how symptoms andtreatment outcomes are assessed (NIH (2003). Re-Engineering the ClinicalResearch Enterprise. Bethesda, Md.: NIH, which is incorporated herein byreference in its entirety). Thus, CAT can take a prominent place in theassessment of HRQOL. It is therefore important to assess how an elderlypopulation that has limited experience with computers can react tocomputerized assessments and how these can be designed to be mostacceptable to elderly patients.

In accordance with an embodiment of the present invention, a conceptualframework for constructing disease-specific and generic HRQOL measuresfor clinical outcomes research makes important distinctions betweendomains of health and their operational definitions. (see FIG. 4). FIG.4 portrays a specific-generic continuum (Ware, Jr., 1995; Wilson I B &Cleary P D (1995). Linking clinical variables with health-relatedquality of life. A conceptual model of patient outcomes. JAMA, 273,59-65, which is incorporated herein by reference in its entirety),rather than a simple categorization of specific and generic concepts andmeasures. For example, as one moves from the left to the right of FIG.4, the measures change from being the most highly specific and objectiveclinical measures (box 1), to disease-specific symptoms (box 2), tospecific measures of disease impact (box 3), and to generic measuresthat are applicable across chronic disease and treatment groups.Measures in boxes 3 & 4 of FIG. 4 attempt to capture specific andgeneric HRQOL impact, for example, with questions about limitations inrole participation due to a specific disease versus questions about thesame limitations without attribution to a specific disease,respectively.

Measures on the left (boxes 1 & 2) are the most specific and, therefore,useful in making a diagnosis and in determining the severity of aspecific condition (Patrick D L & Erickson P (1988). Assessinghealth-related quality of life for clinical decision-making. In Walker S(Ed.), Quality of life: assessment and application (pp. 9-49). London:MTP Press; and Deyo R A & Patrick D L (1989). Barriers to the use ofhealth status measures in clinical investigation, patient care, andpolicy research. Med. Care, 27, S254-S268; and Patrick D L & Deyo R A(1989). Generic and disease-specific measures in assessing health statusand quality of life. Med. Care,. 27, S217-S232, which are incorporatedherein by reference in their entirety). In contrast, measures on theright (boxes 3 & 4) are more useful in understanding the impact (onfunctioning and well-being) of disease and treatment in the more distalHRQOL terms that matter most to patients. In comparison with box 2,measures in box 3 are HRQOL measures because they capture the social andeconomic impact of disease and treatment. In comparison with box 3, themost generic measures (e.g., Sickness Impact Profile, SF-36 HealthSurvey) in box 4 are not specific to a disease or treatment and,therefore, permit meaningful comparisons across disease and treatmentgroups (e.g., (Bergner M, Bobbitt R A, Kressel S, Pollard W E, Gilson BS, & Morris J R (1976). The sickness impact profile: conceptualformulation and methodology for the development of a health statusmeasure. Int.J Health Serv., 6, 393-415; and Stewart A L, Greenfield S,Hays R D, Wells K, Rogers W H, Berry S D et al. (1989). Functionalstatus and well-being of patients with chronic conditions. Results fromthe Medical Outcomes Study [published erratum appears in JAMA Nov. 10,1989;262(18):2542]. JAMA, 262, 907-913, which are incorporated byreference in their entirety).

As previously conceptualized and measured, the gains in specificityachieved using disease-specific HRQOL measures (box 3) have beenachieved at the expense of being able to make meaningful comparisons ofburden across diseases and benefit across treatments using thosemeasures. Among the reasons for this lack of comparability are the lackof standardization of domain content and the lack of standardization ofscoring algorithms across disease impact metrics. In accordance with anembodiment of the invention, major breakthroughs can be achieved from:(a) standardizing the impact domains sampled to represent HRQOL forpurposes of measuring disease-specific outcomes, and (b) standardizingthe calibrations used to estimate impact from the same items acrossdiseases (e.g., limited in social activity because of diabetes, limitedin social activity because of heart failure).

This conceptual framework of the present invention also makes usefuldistinctions between the content of measures and helps to illustrate theimportance of un-confounding measures across the four boxes. Forexample, when symptom frequency and/or severity is assessed and scoredseparately (box 2) and the associated specific impact is assessed andscored separately (box 3), the implications of different symptoms can bemeaningfully studied and interpreted in terms of their impact on HRQOLin specific (box 3) or generic (box 4) terms.

In accordance with an embodiment of the present invention, standardizingspecific and generic domains as much as possible, both conceptually andin terms of operational definitions, could greatly simplify HRQOLassessment for purposes of clinical trials, everyday clinical practice,health care policy evaluation, and general population monitoring.

The development of the disease impact idea of the present inventionbuilds on three findings: a) when measurement is focused on the impactof a single condition, the impact of that condition on different domainsof functional health and well-being (e.g., emotional, social, and rolefunction) is substantially reflected in a single, common dimension ofdisease impact; b) while diseases differ in severity, the ordering ofspecific indicators of functional health and well-being is generally thesame across disease conditions; and c) by using CAT and IRT it ispossible to select questions to match the level of impact experienced bythe patient and get a precise estimate of the overall level of impactusing only a subset of the available items.

A crucial step in the measurement of any phenomenon is to evaluatedimensionality: How many numbers are needed to adequately describe thephenomenon? Research has established that generic health should beconsidered multi-dimensional and be described by a profile of scores(Stewart A L & Ware J E, Jr. (1992). Measuring Functioning andWell-Being: The Medical Outcomes Study Approach. London: Duke UniversityPress, which is incorporated by reference in its entirety). At most,generic health information can be summarized in two overall components:physical and mental health (Ware J E, Jr., Kosinski M, Bayliss M S,McHorney C A, Rogers W H, & Raczek A (1995). Comparison of methods forthe scoring and statistical analysis of SF-36 health profile and summarymeasures: summary of results from the Medical Outcomes Study. Med Care,33, AS264-79; and Essink-Bot M L, Krabbe P F, Bonsel G J, & Aaronson N K(1997). An empirical comparison of four generic health status measures.The Nottingham Health Profile, the Medical Outcomes Study 36-itemShort-Form Health Survey, the COOP/WONCA charts, and the EuroQolinstrument. Med Care, 35, 522-537, which are incorporated by referencein their entirety). However, when analyzing items on the impact of aspecific disease (migraine headache) it was discovered that all itemsconcerning the impact of headache (that is, items specificallymentioning headache) fit a unidimensional measurement model (Bjorner JB, Kosinski M, & Ware J E, Jr. (2003b). The feasibility of applying itemresponse theory to measures of migraine impact: a re-analysis of threeclinical studies. Qual Life Res, 12, 887-902, which is incorporated byreference in its entirety) even when generic items covering similarconcepts fit a multi-dimensional model. The likely reason for thisfinding is that responses to the generic items are affected bycomorbidities. This observation has subsequently been confirmed inindependent studies, as discussed herein. (Bjorner J B, Kosinski M, &Ware J E, Jr. (2003c). Using item response theory to calibrate theHeadache Impact Test (HIT) to the metric of traditional headache scales.Qual Life Res, 12, 981-1002, which is incorporated by reference in itsentirety; and Kosinski et al., 2004). In accordance with an embodimentof the present invention, the Computerized Adaptive Testing of DiseaseImpact (Disease Impact CAT) aims at assessing the disease impact on thefollowing major HRQOL domains: physical, social, role, emotional, andcognitive functioning. A new innovative approach of unifying thedisease-specific and generic HRQOL assessment of disease impact isdisclosed herein. The Disease Impact CAT of an embodiment of the presentinvention can produce disease-specific impact scores, which can becomparable on a standard common metric across different diseases.

The basic idea of the disease impact approach of an embodiment of thepresent invention is illustrated in FIG. 1, which shows the componentsof disease impact items. A list of functions that may be affected bydisease has been established. In a specific assessment of an embodimentof the present invention, a question is asked whether a particularphysical, social, role, emotional, or cognitive function is affected bythe disease in question.

The measurement properties of each item of an embodiment of the presentinvention is evaluated through item response theory (van der Linden W J,Hambleton R K. Handbook of Modern Item Response Theory. Berlin:Springer, 1997, which is incorporated by reference in its entirety )(IRT). IRT is a set of statistical models that describe the probabilityof choosing a particular item response as a function of itemcharacteristics and the level of disease impact for the particularrespondent.

FIGS. 2A-2C demonstrate the IRT model of an embodiment of the presentinvention for two disease impact items and their relation to thepopulation distribution of disease impact for two diseases. Each line inFIGS. 2A and 2B represent the probability of choosing each item responsefor a given level of disease impact. The lines in FIGS. 2A and 2B aredefined by a set of item parameters that are characteristics of theparticular item. These parameters determine the position of the curvesalong the horizontal axis and the steepness of the curves. In FIG. 2B,the curves for the second item on social avoidance is shifted to theright compared to the first item illustrated in FIG. 2A on irritability,indicating that the second item illustrated in FIG. 2B measures a moresevere level of disease impact. Once item parameters have beenestimated, it is possible to use the item parameters to estimate thelevel of disease impact for a particular patient or a group of patientsusing standard IRT methods (Bock R D. Estimating item parameters andlatent ability when responses are scored in two or more nominalcategories. Psychometrika 1972;37:29-51; Warm T A. Weighted likelihoodestimation of ability in item response theory. Psychometrika1989;54:427-50; Mislevy R J. Estimating latent distributions.Psychometrika 1984;49:359-81; Mislevy R J. Estimation of Latent GroupEffects. J.Am.Stat.Assoc. 1985;80:993-7, which are incorporated byreference in their entirety). FIG. 2C illustrates the estimateddistribution of disease impact for two diseases: asthma and congestiveheart failure (CHF). The columns to the left of FIG. 2C represent peoplewith no measurable impact of their disease in the domains examined. Therest of FIG. 2C illustrates the distribution of impact for people withsome impact. On average, CHF has higher impact than asthma, as shown inFIG. 2C. The IRT model used for the analysis of the disease impact itemsis the Generalized Partial Credit Model (Muraki E. A Generalized PartialCredit Model. In van der Linden W J, Hambleton R K, eds. Handbook ofModern Item Response Theory, pp 153-64. Berlin: Springer, 1997, which isincorporated by reference in its entirety).

The unique aspect of the disease impact approach of the presentinvention is the identification of a set of items that has stable itemparameters (relative to the other items in the set) across diseases. Forexample, as shown in FIG. 2A the same model applies for item 1 when usedin asthma and in CHF (and likewise for item 2 as shown in FIG. 2B). Thismeans that the probability of selecting a specific response category fora given level of disease impact is the same—regardless of the specificdisease. This property of an embodiment of the present inventionestablishes the common metric that allows for the comparison of diseaseimpact across diseases. The stability of item parameters can be testedthrough techniques for analysis of differential item functioning (DIF)(Holland P W, Wainer H. Differential item functioning. Hillsdale, N.J.:Lawrence Erlbaum Associates, Inc, 1993, which is incorporated byreference in its entirety). The stability across disease attributions isnot a given. FIGS. 3A and 3B illustrate an IRT model of an embodiment ofthe present invention for an item that did not fulfill the requirementof stability across disease conditions, i.e., an item that was notstable enough to be included in the item bank of an embodiment of thepresent invention. For a given level of disease impact (as assessed byall other items), patients with CHF tended to give a high rating of painthan people with asthma. Although the difference between curves may seemminor when inspected visually, a statistical test for DIF was highlysignificant.

To develop the Disease Impact CAT of the present invention, an item bankwas built, which can be implemented into the software of the presentinvention. For building the item bank and constructing a standardizedmetric of disease impact across different disease groups an item pool of53 questions, administered via the Internet, was analyzed. Data wascollected from N=2,906 subjects suffering from the following fivechronic conditions: Asthma (N=1.001), Rhinitis (N=1.001), OsteoArthritis(N=601), Congestive Heart Failure (N=202) and Rheumatoid Arthritis(N=103). Data was collected. All subjects were asked to complete thesame 53 disease impact items, but with different disease conditionsspecified in the item text. Thus, the item text was specific to thedisease condition of the particular respondent, i.e., subjects sufferingfrom asthma were asked ‘In the past 4 weeks how much of the time didyour asthma limit you in performing your usual daily activities . . .?’, whereas subjects suffering from congestive heart failure receivedthe questions ‘In the past 4 weeks how much of the time did your heartdisease limit you in performing your usual daily activities?’.

The development of the item bank of the present invention involved twodata analytic tasks: 1) test that all the disease impact items measurethe same underlying concept (i.e., investigate the unidimensionality ofthe items); 2) evaluate the stability of item parameters, by testing forDIF.

Unidimensionality was evaluated using exploratory and confirmatoryfactor analyses as described in (Bjorner J B, Kosinski M, Ware J E, Jr.Calibration of an item pool for assessing the burden of headaches: anapplication of item response theory to the headache impact test (HIT).Qual Life Res 2003;12:913-33, which is incorporated by reference in itsentirety). Initial data analyses was performed separately for eachdisease group using factor analytic methods for categorical data(Muthen, B. O. and Muthen, L. Mplus User's Guide. 3(3). 2004. LosAngeles, Muthén & Muthén, which is incorporated by reference in itsentirety). Using these approaches a set of items that measures oneunidimensional concept of disease impact was established.

The data sets for the five disease groups were combined to investigateDIF across the groups. Investigating DIF was crucial in that the goalwas a stable scaling of disease impact items across all disease groups.A stable standardized scaling is achieved, if the estimated itemparameters are similar across the disease groups (as was the case foritem 1 and for item 2, as shown in FIGS. 2A and 2B, respectively).

In contrast, items showing DIF across disease group (like the item, asshown in FIGS. 3A and 3B) cannot be used to standardize scores acrossdiseases.

The DIF analyses showed that it was possible to identify a set of itemswith stable item parameter estimates across the disease groups. However,some items that directly reflected the mechanism of only a subset ofdiseases (e.g., items assessing single disease specific symptoms)functioned differently across diseases and thus had to be excluded. Theitems meeting the assumption of unidimensionality and showing nomeaningful DIF across the disease groups were selected and can form theitem bank of the Disease Impact CAT of an embodiment of the presentinvention. The standardized item parameter estimations of these itemscan be used by the software of the present invention to guide the itemselection of the Disease Impact CAT of the present invention and toenable the disease impact scoring of this new tool of the presentinvention.

Thus, the disease impact approach of the present invention builds on thenew idea that it is possible to identify a set of disease specific itemsthat functions the same way regardless of disease attribution. Thishypothesis was tested by investigations of unidimensionality andstatistical tests for DIF, and a set of items that functions the sameway across different disease groups was established. This item set isused to establish the common disease impact metric of the presentinvention that allows for the comparison of disease impact acrossdiseases.

EXAMPLE 1

Secondary IRT analyses of data for the SF-36 Health Survey and otherquestionnaires measuring the same HRQOL concepts was conducted toexplore the practical implications of IRT and CAT for clinical researchand practice.

Questionnaires self-administered by chronically ill patients (N=2,753)participating in the Medical Outcomes Study (MOS) were reanalyzed(Stewart & Ware, Jr., 1992; Tarlov A R, Ware J E, Jr., Greenfield S,Nelson E C, Perrin E, & Zubkoff M (1989). The Medical Outcomes Study. Anapplication of methods for monitoring the results of medical care. JAMA,262, 925-930, which is incorporated by reference in its entirety). Thepotential practical implications of IRT models and CAT-based assessmentswere clearly apparent from analyses where CAT was simulated using realdata from people who answered all items in the item bank (Ware J E, Jr.,Bjorner J B, & Kosinski M (1999). Dynamic Health Assessment: The Searchfor More Practical and More Precise Outcome Measures. Quality of LifeNewsletter, 11-13; and Bjorner J B & Ware J E, Jr. (1998). Using ModemPsychometric Methods to Measure Health Outcomes. Medical Outcomes TrustMonitor, 3, 12-16, which are incorporated by reference in theirentirety). In such “real data simulations”, respondent burden wasdramatically reduced for the lowest-scoring patients (bottom third inmental health), for whom the highest standard of precision was set forCAT assessments. Specifically, 92 percent required only five or fewerquestionnaire items to satisfy the “clinical” precision standard for anindividual patient and the product-moment correlation betweenfull-length (31-item) and dynamic one-minute (five or fewer items)assessments was very high (r=0.985) in the MOS. Cross-sectional tests ofthe discriminant validity and longitudinal tests of responsiveness werealso very favorable for scores estimated dynamically, in comparison withtraditional scoring of the full-length questionnaire. Thus, in the MOS,scores estimated using the CAT algorithms were virtually interchangeablewith scores based on a static “full-length” form throughout the scalerange.

Based on these encouraging preliminary results, studies were conductedto develop item banks for the eight domains represented by the SF-36Health Survey. Data were collected in samples drawn from the generalpopulation using computer interface and telephone interviews. A total of5,700 questionnaires were administered through the Internet. Thoserandomly assigned to one of the studies were asked a standard set ofdemographic questions (age, sex, race/ethnicity, marital status, etc.)plus screening questions to ensure that the sample was representative ofthe general population. Another 4,800 questionnaires were administeredby telephone interview. To obtain a representative sample ofrespondents, telephone interviewing was conducted using a Random DigitDialing methodology. For seven banks, items from a variety of commonlyused tools were included to allow cross-calibration. For each item bank,a careful psychometric analysis was conducted to identify the bestitems. The items remaining in the banks have been found to fit aunidimensional IRT model and to be without differential item functionfor gender, age, education, and race/ethnicity.

EXAMPLE 2

The first fully functioning CAT for medical outcomes was the DYNHA-HIT(Ware J E, Jr., Bjorner J B, & Kosinski M (2000). Practical implicationsof item response theory and computerized adaptive testing: a briefsummary of ongoing studies of widely used headache impact scales.Med.Care, 38, II73-II82, which is incorporated by reference in itsentirety). This work was initiated by a re-analysis of data from threeclinical trials of migraine treatment showing that IRT analysis couldsuccessfully be applied to a traditional HRQOL tool (Bjorner et al.,2003b) and that CAT-based scores were as precise or more precise thanscores based on traditional tools and methods in evaluating treatmentoutcome (Kosinski M, Bjorner J B, Ware J E, Jr., Batenhorst A, & Cady RK (2003b). The responsiveness of headache impact scales scored using‘classical’ and ‘modern’ psychometric methods: a re-analysis of threeclinical trials. Qual Life Res, 12, 903-912, which is incorporated byreference in its entirety). These results prompted development of aCAT-based dynamic headache impact test (DYNHA-HIT). DYNHA-HIT wasdeveloped from a new item bank comprised of items from widely-usedmeasures of headache impact. The questionnaires were administered overthe telephone by trained interviewers to a national sample of adultssuffering from disabling headaches. Data were analyzed usingconfirmatory factor analysis for categorical data, analysis ofdifferential item functioning, and IRT analyses (Bjorner et al., 2003a).A main finding of these analyses was that all the traditional headachescales were found to measure one unidimensional construct of headacheimpact, so nearly all items were included in the HIT item pool. Linkshave been maintained to these source measures, so that all items fittingthe IRT model can be calibrated on a common metric and results can becompared across measures. A conversion table has been developed andpublished to ease comparison of results for these widely-usedinstruments in relation to DYNHA-HIT, and can be used for the purposesof transferring interpretation guidelines for the dynamic scores back tothe metric of scale scores based on traditional summated rating methods(Bjorner et al., 2003c).

To determine whether substantial reductions in respondent burden arepossible while maintaining acceptable standards of score precision,simulations of CAT were performed and actual Internet-based CATadministrations among two large samples of recent headache suffererswere evaluated using accepted clinical criteria (Ware, Jr. et al.,2003).

The results strongly suggest that very large reductions in respondentburden (e.g., 90%) are possible using IRT parameters and CAT-basedmethods of administering HIT items. Further, results from preliminaryempirical tests of validity that closely approximate the intended usesof HIT in clinical research suggest that very brief DYNHA-HITassessments can be programmed to satisfy the precision requirements ofboth individual patient screening and outcomes monitoring over a widerange of headache impact levels.

As summarized elsewhere (Ware, Jr. et al., 2003), observations of actualCAT assessments of headache-related disability on the Internet suggestthat substantial reductions in respondent burden (from 53 full-lengthitems to five or fewer items) are possible, while achieving clinicalstandards of precision. The widespread interest in DYNHA-HIT since itslaunch on the Internet demonstrates the feasibility of usingInternet-based dynamic assessments to measure health status. Theassessments are precise, and brief. Data from 19,000 “real world” takersof DYNHA-HIT confirm results of previous studies by showing DYNHA-HIT tobe valid in differentiating respondents on the basis of headachecharacteristics such as severity and frequency. For example, patientswith very high impact scores are very likely to have a disablingheadache—such as a cluster headache, severe tension headache ormigraine. DYNHA-HIT scores reflect the impact of headache on a person'severyday functioning, using a standard metric so results can becompared. DYNHA-HIT serves as a systematic source of information forclinicians, yields information not always detected by physicalexamination, and helps monitor populations and/or individuals receivingtreatment for headache.

To further enhance the flexibility of headache impact assessment in avariety of settings HIT-6™ was developed. This tool is a fixed-lengthshort form version of DYNHA-HIT for paper and pencil administration witha simplified scoring system intended to match the IRT score as closelyas possible (Kosinski M, Bayliss M S, Bjorner J B, Ware J E, Jr., GarberW H, Batenhorst A et al. (2003a). A six-item short-form survey formeasuring headache impact: the HIT-6. Qual Life Res, 12, 963-974, whichis incorporated by reference in its entirety). Construction of the HIT-6short-form was achieved using the item bank developed for DYNHA-HIT. Thetool has been found to be reliable and valid for group-levelcomparisons, patient-level screening, and to be responsive to changes inheadache impact. The HIT-6 items were shown to cover a substantial rangeof headache impact as defined by the larger item bank and to representthe content areas found in most widely used headache impact tools(Kosinski et al., 2003a). The HIT-6 has been translated for use in 27countries, which optimizes opportunities for international applicationand comparability across diverse groups (Gandek, B., Alacoque, J., Uzun,V., Andrew-Hobbs, M., & Davis, K. Translating the Short-Form HeadacheImpact Test (HIT-6) in 27 Countries: Methodological and ConceptualIssues. Qual Life Res, (in press), which is incorporated by reference inits entirety). In conclusion, both the DYNHA-HIT and HIT-6 showexcellent criterion validity and responsiveness to change. However, atevery score level DYNHA-HIT was more accurate than HIT-6 (Ware, Jr. etal., 2003).

EXAMPLE 3

Based on the results for headache impact as described supra, a study wasconducted to investigate whether the scaling of indicators of functionalhealth and well-being impacted by disease would be stable across diseaseconditions. If the scaling is stable (reflected in stable IRT itemparameters across disease groups), the items have the same relativeposition on a “ruler” of disease impact regardless of disease. Ingeneral, this has been the case for the diseases in which the full setof indicators were tested to date: Rhinitis, Asthma, Osteoarthritis,Rheumatoid Arthritis, and Congestive Heart Failure. However, indicatorsthat directly reflected the mechanism of some disease (e.g., questionsdirectly about symptoms) functioned differently for these diseases andwere, therefore, excluded. Based on these results, a bank of 37indicators was constructed with stable scaling over the conditionsevaluated. Further, based on responses to a smaller number of items theimpact of 43 diseases/conditions were scaled. FIG. 5 illustrates thecomponents of disease impact items of an embodiment of the presentinvention. FIG. 5 shows examples of indicators of functional health andwell-being ordered, on the basis of preliminary IRT calibrations, fromleast to most severe in terms of the relative level of impact defined byeach. FIG. 5 also lists examples of conditions in the order of theirrelative average impact (from least to most severe). Accordingly, theimpact of the more severe conditions (e.g., Congestive Heart Failure)can be most efficiently estimated from indicators assessing the moresevere range of the impact continuum in FIG. 5 (e.g., “feel like aburden on others”).

In particular, the Disease Impact study, as described supra, waslaunched to investigate whether the scaling of indicators of diseaseimpact would be stable across disease conditions and if so, to develop abank of disease impact indicators. Five diseases were investigated:Asthma, Congestive Heart Failure, Osteoarthritis, Rheumatoid Arthritis,and Rhinitis, and data was collected regarding the aforementioned fivediseases. Potential participants were asked a standardized set ofdemographic questions (age, sex, marital status, etc.) plus thescreening questions for the study. Participants eligible for this study:(1) were ages 18 years or older; (2) were not employed by any marketingresearch or advertising company; and (3) screened positive for one ofthe five conditions. The hypothesis of unidimensionality of the diseaseimpact items was tested using factor analysis for categorical data(Muthen B O & Muthen L (2001). Mplus User's Guide (Version 2) [Computersoftware]. Los Angeles: Muthén & Muthén, which is incorporated byreference in its entirety) in each of the five disease groups and usingmultigroup factor analysis for a combined analysis of all groups. Thehypothesis of stable scaling of the items across disease groups wasfurther investigated by tests for differential item functioning (DIF)using the logistic regression approach (Zumbo B D (1999). A handbook onthe Theory and Methods of Differential Item Functioning (DIF): LogisticRegression Modeling as a Unitary Framework for Binary and Likert-type(Ordinal) Item Scores. Ottawa,ON: Directorate of Human ResourcesResearch and Evaluation, Department of National Defense, which isincorporated by reference in its entirety). While most items did notshow signs of DIF, a few items did. These indicators directly reflectedthe mechanism of one of the diseases (e.g., questions directly aboutsymptoms). Based on these results, a bank of 37 indicators wasconstructed with no DIF across the five disease groups. FIG. 5 showsexamples of indicators and conditions and how they combine to form adisease impact item. Based on these items, impact scores could beestimated and compared across the five disease groups (see Table 1).

TABLE 1 Sample size and disease impact score for 5 disease conditionsCondition N Mean¹ Std. Dev. Asthma Impact 1001 49.38 8.89 CongestiveHeart Failure 202 56.76 11.91 Impact Osteoarthritis Impact 601 51.619.82 Rheumatoid Arthritis Impact 101 58.69 7.71 Rhinitis Impact 100148.45 9.61 ¹The scale is designed so that the average person with achronic disease scores 50, and a score of higher than 50 is worse

The software of an embodiment of the present invention (described supra)is available through the Internet and as a stand-alone desktopapplication. The assessment begins with administration of a global itemthat is selected a priori on the basis of the range it covers. DYNHA'slogic for item selection and score estimation builds on item responsetheory (IRT) and is quite general. However, DYNHA has been optimized forclinical use. Among the important capabilities in this context are: 1)The ability to handle polytomous rank scales items. Among the IRT modelshandled by DYNHA are the generalized partial credit model, the partialcredit model, and the rating scale model; 2) Availability of additionalitem selection criteria, to ensure the content validity of theassessment. Thus, assessment within a domain can be balanced withregards to subdomains; 3) Immediate feedback to patients and providers,including interpretation guidelines, norm group score benchmarks, andevaluation of patient response consistency, according to the IRT model.Such information is useful to identify potential misreading of questionswhich can be clarified with the patient immediately after theassessment, in turn leading to improved assessment quality; and 4) Twodifferent ways of IRT scoring: the standard Expected a Posteriori (EAP)scoring (Bock R D & Mislevy R J (1982). Adaptive EAP estimation ofability in a microcomputer environment. Applied Psychol Measur, 6,431-444, which is incorporated by reference in its entirety) andWeighted Maximum Likelihood (WML scoring (Warm T A (1989). Weightedlikelihood estimation of ability in item response theory. Psychometrika,54, 427-450, which is incorporated by reference in its entirety).

In accordance with an embodiment of the present invention, a DiseaseImpact CAT of a comprehensive patient-based system for assessing diseaseimpact that yields user-friendly reports likely to enhancepatient-provider communication and improve decision-making can bedeveloped.

In accordance with an embodiment of the present invention software canbe programmed to implement the computerized dynamic assessment (DYNHA)of disease impact with a variety of diseases. This new comprehensiveassessment can be designed by a team comprised of measurement experts.The clinical partners, who have experience with a dynamic assessment ofheadache impact, can assist with patient recruitment, participate in thedetermination of the content and format of the patient and clinicianreports, and contribute to the development of practical, usefulinterpretation guidelines. These guidelines can foster patient-cliniciancommunication, inform treatment decisions, and support individualpatient monitoring. Previously collected data can be used to test thestability of item calibrations across age groups and to develop clinicalbenchmarks for interpretation of the disease impact scores. A User'sAcceptance evaluation can be adapted from previous evaluations to assesspatient experience completing the instrument, and to gather specificfeedback on the reports. The assessment can also include asociodemographic survey and chronic conditions checklist. A SoftwareEngineering team can program the dynamic assessment system (DiseaseImpact CAT). Specifically, the overall assessment can be tailored for‘seamless’ items administration and report generation. A User'sAcceptance survey and chronic conditions checklist can be collected foranalysis.

In accordance with an embodiment of the present invention, the presentinvention can be evaluated on the feasibility of administering therelatively short but comprehensive Disease Impact CAT to middle aged andelderly patients with chronic diseases, evaluate administrative data(e.g., CAT item usage) and evaluate reports that can be printed uponcompletion of the assessment. The specific objectives of the presentinvention include: 1) Assessment of respondent burden, range of levelsmeasured, floor and ceiling effects, and item usage; 2) Test of the fitof the IRT model for each respondent through evaluation of responseconsistency (Drasgow F, Levine M V, & Williams E A (1985).Appropriateness measurement with polychotomous item response models andstandardized indices. Br Journal of Math Stat Psychol, 38, 67-86, whichis incorporated by reference in its entirety) Patients' evaluation ofthe CAT and the patient feedback report; and 4) Clinicians' evaluationof the usefulness of the clinician feedback report.

In accordance with an embodiment, the results of the present inventioncan be analyzed, interpreted and summarized.

This approach can allow the Disease Impact CAT of the present inventionto be developed and tested, test the user experience of the assessmentand the feedback report, and improve the user interface for anadditional project.

The evaluation of the equivalence of item calibrations across age groupsand the development of clinical benchmarks can be based on previouslycollected data from the Disease Impact study. Five diseases wereinvestigated: Asthma, Congestive Heart Failure, Osteoarthritis,Rheumatoid Arthritis, and Rhinitis, and data was collected regarding theaforementioned five diseases. Potential participants were asked astandardized set of demographic questions (age, sex, marital status,etc.) plus the screening questions for the study. Participants eligiblefor this study: (1) were ages 18 years or older; (2) were not employedby any marketing research or advertising company; and (3) screenedpositive for one of the five conditions. In addition to the diseaseimpact questions, participants received a standard disease-specificquestionnaire for their particular disease. These data can be used todevelop clinical benchmarks.

For example, a sample of 100 patients 45 years and older with one of thefollowing chronic conditions: Osteoarthritis, Depression, ChronicObstructive Pulmonary Disease, Diabetes, and Osteoporosis. The diseasegroups have been selected to include diseases that are common among theelderly and likely represent a large spread in impact. One of thedisease groups is included for which the item banks were originallydeveloped and four new diseases to be able to evaluate the consistencyand usefulness of the disease impact approach beyond the groups forwhich it originally was developed. Depression is included, to be able toevaluate the usefulness of the approach for mental health problems.Participants can be sampled from two primary care practices that arepart of the Primary Care Network. Patients can be selected to ensureequal representation of the three age groups: 45-59 years, 60-69 years,and 70 years and older. This selection can allow an evaluation andcomparison of the feasibility of CAT in different age groups. Allparticipants can be required to speak English as their primary languageto avoid prohibitive translation costs.

Protocol can be established that is acceptable by national medicalreview boards.

Sample participants can be recruited into a study to evaluate thefeasibility, efficiency and accuracy of the Disease Impact CAT system ofthe present invention. They can be asked to complete (a) the dynamicDisease Impact CAT, (b) the static SF-12v2 Health Survey, and (c) abrief post-assessment evaluation. Assessments using the Disease ImpactCAT with the DYNHA software can use the Disease Impact item bank andadminister the five items that are most informative for each respondent.The SF-12v2 Health Survey can be used to evaluate the relationshipbetween Disease Impact score and generic measures of HRQOL and help toemulate the kind of comprehensive assessment described herein. Data canbe entered on a portable computer residing in each clinic. Aftercompletion of data collection, data can be analyzed. All data can behandled without any patient personal identifiers.

The Disease Impact CAT of the present invention measures the impact of aspecific disease on a person's functioning and well-being. An example ofa disease impact item in the context of Osteoarthritis is “In the past 4weeks, how much of the time has your osteoarthritis interfered with howwell you dealt with family, friends, and others who are close to you?”Responses included “none of the time”, “a little of the time”, “some ofthe time”, “most of the time”, and “all of the time”. The disease impactitem pool currently consists of 37 items. Survey questions aredynamically selected to match each respondent's level of impact and toachieve a pre-set level of score precision or respondent burden. Theresult is a very brief assessment that meets clinical standards ofprecision over a very wide range, while substantially (more than 90% formost patients) reducing respondent burden and data collection costs.

User's Acceptance Survey can be constructed to obtain a standardizedevaluation of each respondent's experience in completing a comprehensiveHRQOL Assessment. As in previous studies (Bayliss et al., 2003)questions can include user's ratings of the overall format andpresentation, ease of understanding instructions for administration,survey length, simplicity/clarity of language, number andappropriateness of response choices, feedback report content and layout,relevance, and usefulness in care planning and evaluation.

Other—Respondents can also be asked to complete questions aboutsociodemographic characteristics and clinical variables used in previousstudies (as described above).

These analyses can use data from the Disease Impact Study of the presentinvention. The following analyses can be performed:

Evaluate the equivalence of item calibrations across age groups. Theseanalyses can evaluate DIF (Holland P W & Wainer H (1993). Differentialitem functioning. Hillsdale, N.J.: Lawrence Erlbaum Associates, Inc,which is incorporated by reference in its entirety) across age groupsusing logistic regression methods (Swaminathan H & Rogers J H (1990).Detecting Differential Item Functioning Using Logistic RegressionProcedures. J Educ Measur, 27, 361-370, which is incorporated byreference in its entirety). For large item pools, logistic regressionmethods are more practical than IRT-based methods. Further, the logisticregression approach allows a fine gradation of age groups, providingmore statistical power. DIF is tested by measuring associations betweeneach item and age group, while conditioning on the sum score. Bothuniform DIF (differences in threshold parameters) and non-uniform DIF(differences in slope parameters) can be assessed for each item. Itemscan be considered as exhibiting significant DIF if two criteria are met:statistical significance (p<0.05 after correction for multiple testing)and magnitude of DIF (R² difference) of at least 2% using Nagelkerke R²(Nagelkerke N J D (1991). A Note on a General Definition of theCoefficient of Determination,” Biometrika, 78, 691 -692. Biometrika, 78,691-692, which is incorporated by reference in its entirety). If DIF isfound, the possibility of correcting for DIF using IRT-based methods canbe explored (Thissen D, Steinberg L, & Wainer H (1993). Detection ofDifferential Item Functioning Using the Parameters of Item ResponseModels. In Holland P W & Wainer H (Eds.), Differential Item Functioning(pp. 67-113). Hillsdale N.J.: Lawrence Erlbaum Ass; and Muraki E (1999).Stepwise Analysis of Differential Item Functioning Based onMultiple-Group Partial Credit Model. Educ Measur, 36, 217-232, which areincorporated by reference in their entirety).

Develop clinical benchmarks for interpretation of disease impact scores.The benchmarks can be developed directly from the IRT model (see Ware,Jr. et al., 2003) and also from the disease-specific questionnairesadministered for Osteoarthritis, for example.

The CAT system of the present invention can be implemented on smallportable computers with a touch-screen technology to maximizeflexibility in the clinical setting. The assumption that elderlypatients will prefer a touch-screen over use of a keyboard or a mousecan be evaluated. A test dataset can be used to evaluate the accuracy ofoutput from the new comprehensive DYNHA software and scores estimatedfrom each specific and generic module, prior to fielding the study.

These reports can contain guidelines for score interpretation.Interpretation guidelines can be based on the typical distribution ofimpact scores for the particular patient group and on clinicalbenchmarks developed from the Disease Impact Study data. The clinicianreport can contain additional technical information (e.g., the precisionof the score and the consistency of the patients' responses).

The computerized dynamic health assessment (DYNHA™) software of anembodiment of the present invention that can be used in the tests ofdynamically-administered Disease Impact CAT has a number of featuresthat can be evaluated in terms of psychometric performance and userevaluation:

Respondent burden, range of levels measured, floor and ceiling effects,and item usage. The number of items needed for the CAT algorithm toachieve a precise score and the amount of time per administration (inminutes) can be evaluated. Further, the score distribution is evaluatedand whether any patients' scores are at the floor or ceiling is tested(lowest and highest possible score). Item usage can be described (numberof times each item is administered).

Evaluation of response consistency. The initial evaluation of thestability of item parameters across disease groups relied on tests ofdifferential item functioning. In accordance with an embodiment of theinvention, evaluation of response consistency is used (Drasgow et al.,1985) for the same purpose (Custers J W, Hoijtink H, van der N J, &Helders P J (2000). Cultural differences in functional statusmeasurement: analyses of person fit according to the Rasch model.Qual.Life Res, 9, 571-578, which is incorporated by reference in itsentirety). Such IRT fit methods build on the already established IRTmodel to generate person-based fit indices. Low response consistency ina particular group suggests that the general IRT model is notappropriate for this disease condition. Since a fit statistic isgenerated for each person, this methodology can be used with smallsample sizes (Custers et al., 2000).

Patients' evaluation of the CAT and the feedback report. Survey feedbackregarding the acceptability of the Disease Impact CAT can be examinedbased on the User's Acceptance Survey.

Clinicians' evaluation of the usefulness of the clinician feedbackreport. This evaluation can be performed through semi-structuredinterview with the involved clinicians.

Preliminary evaluations of the feasibility of a Disease Impact CAT ofthe present invention in clinical settings can be achieved and theanalyses can be primarily descriptive (e.g., item usage, number of itemsrequired to meet pre-set precision standards, and ratings ofacceptance). Evaluation of response consistency can be performedseparately for each patient. Thus, the data collected can be adequate toimplement the analyses.

Additionally, the general applicability of a comprehensive DiseaseImpact CAT Assessment System of the present invention standardizedacross chronic diseases/conditions can be developed and evaluated, interms of psychometric performance (equivalence across diseases andreliability, validity and precision of scores) and clinical usefulnessfor randomized trials and everyday practice.

Subjects can be English-speaking adults, ages 45 and older. Non-Englishspeaking subjects might not be included due to costs of translationservices. A commitment to the inclusion of a representative sample ofparticipants from minority populations can be made. In following,efforts can be made to recruit a sample that reflects roughly equivalentproportions for gender and race/ethnicity based on the 2000 U.S.population Census estimates for those in the age group 45 years andolder (see Table 2).

TABLE 2 Sample Enrollment Table Study Title: Computerized AdaptiveAssessment of Disease Impact - Study Total Sample Enrollment: 100 SAMPLEENROLLMENT: Number of Subjects Sex/Gender Females Males Total EthnicCategory Hispanic or Latino 7 6 13 Not Hispanic or Latino 47 40 87Ethnic Category Total of All Subjects* 54 46 100 Racial CategoriesAmerican Indian/Alaska Native 1 1 2 Asian 4 3 7 Native Hawaiian or OtherPacific Islander 1 1 2 Black or African American 7 6 13 White 41 35 76Racial Categories: Total of All Subjects* 54 46 100 *The “EthnicCategory Total of All Subjects” must be equal to the “Racial CategoriesTotal of All Subjects.”

Sample Enrollment Table (Secondary Analyses) Study Title: Disease ImpactSurvey Total Sample Enrollment: 2,908 SAMPLE ENROLLMENT TABLE (SecondaryAnalyses): Number of Subjects Sex/Gender Females Males Total EthnicCategory Hispanic or Latino 53 28 81 Not Hispanic or Latino 1932 8952,827 Ethnic Category: Total of All Subjects* 1,985 923 2,908 RacialCategories American Indian/Alaska Native 16 10 26 Asian or PacificIslander 40 28 68 Black or African American 65 19 84 White† 1,746 8122,558 Other 31 10 41 Preferred not to answer 87 44 131 RacialCategories: Total of All Subjects* 1,985 923 2,908 *The “Ethnic CategoryTotal of All Subjects” must be equal to the “Racial Categories Total ofAll Subjects.”

Subjects can be asked to complete a survey intended to assess the impactof their disease on their daily life and a post-assessment evaluation.The exclusion criterion can be any respondent that does not speakEnglish as a primary language or is unable to answer questionnaires dueto cognitive limitations. Subjects participating in this study can notundergo any physical testing.

The risks of participation in this study are very minimal. There is notreatment or physical testing beyond the standard clinical proceduresinvolved.

The Nurse/Study Coordinator can identify patients through the clinicsites at the Primary Care Network who meet eligibility criteria.Patients can be asked to participate in the study by their cliniciansand those who indicate an interest can be asked to meet with theNurse/Study Coordinator, who can explain the study and present theconsent information in writing and verbally. The assessment can beconducted by the Nurse/Study Coordinator, who can obtain signed consentprior to survey administration. The Nurse/Study Coordinator can takeinto account and record any participant-reported physical and cognitivelimitations and use of assistive devices. At the meeting, theNurse/Study Coordinator can review the consent information, obtain asigned consent form, and administer the instrument.

Data from the computerized assessment can be uploaded from the localcomputer. The clinic site can use only code number identification in thedata set or on the paper questionnaires. The key linking code numbers toidentifying information can be kept by the local site clinicalcoordinator. Study data can be maintained in secure computers meetingdata security standards, including those set forth in Privacy Rule ofthe Health Insurance Portability and Accountability Act (HIPAA) of 1996,the Security Rule of HIPAA, and all other relevant laws and regulations.Protected Health Information (PHI) for patients may not be released fromthe Primary Care Network clinic sites. PHI can only be needed toidentify members for project enrollment. During this period, all PHIrelated data can be stored on secure networks and password protected atthe Primary Care Network clinic sites. Data stored on certainproprietary websites can contain no PHI related data, only a studyidentifier. Because this is a member-based survey asking aboutperceptions of health, significant risks to subjects from completing thesurvey is not anticipated. To reduce risks to subjects, validatedinstruments that have been used in previous research, approved byexternal Institutional Review Boards are used.

All participating personnel in this proposal have either alreadycompleted human subjects training, or can complete Human ParticipantProtections: Education for Research Teams by the National Institutes ofHealth.

The benefit to risk ratio is very high, given the extremely low level ofrisk involved and the value of the information to be gained. Individualsubjects may benefit from participating in the study in that (a) theirunique perspective on their HRQOL is being considered and integratedinto their disease management, and/or (b) they feel a sense ofsatisfaction in contributing to an important project that can lead toimproved outcomes measurement. In addition, patients can be providedwith a financial incentive for their participation in the study.

Risks to participants are very low in relation to benefit gained throughparticipation in a study that provides a direct comprehensive healthstatus assessment. This may serve as an opportunity for some subjects tofeel empowered in that by participating, they are furthering the fieldof disease impact assessment and contributing to improvingclinician-patient communication.

The sample is intended to be representative of the population 45 yearsand older. With regard to inclusion of women, the full spectrum ofrepresentation is sought, and targeted enrollment can be based on 2000U.S. Census data for gender distribution among those 45 years and older.

The sample is intended to be representative of the population 45 yearsand older. With regard to inclusion of minorities, the full spectrum ofrepresentation is sought, and targeted enrollment can be based on 2000U.S. Census data for race/ethnicity distribution among those 45 yearsand older. Participation of racial/ethnic subgroups is sought to bemaximized, and the study can be conducted at an additional site in orderto achieve the enrollment targets.

Issues applicable to the study of HRQOL and other relevant topics forchildren differ from those that are relevant to adults in thispopulation. The assessment system used in this project is designed foradult patients with chronic conditions. CAT for the pediatric populationin other company projects is being addressed.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the invention, it will be understoodthat the invention may be embodied otherwise without departing from theprinciples of the invention and that various modifications, alternateconstructions, and equivalents will occur to those skilled in the artgiven the benefit of this disclosure, Thus, the invention is not limitedto the specific embodiment described herein, but is defined by theappended claims.

1. A computer based system for assessing the impact of an ailment on ahealth related quality of life (HRQOL) domain of a patient, wherein saidHRQOL domain comprises a plurality of indicators of functional healthand well being, comprising: a microprocessor configured to: generate acustomized test having a plurality of questions for said patient todetermine the impact of said ailment on said HRQOL domain, wherein eachquestion comprises an indicator of functional health and well being as aresult of said ailment, wherein said indicator is stably scaled acrossailments whose impact is to be assessed to establish a standardizedcommon metric for comparing the impact of various ailments; administersaid test by providing one question at a time to said patient; evaluate,after each question, answers provided by said patient to estimate anailment impact score and a confidence level in the accuracy of saidestimated ailment impact score; vary a threshold, after each question,as a function of said estimated aliment impact score duringadministration of said test to said patient; and dynamically modify saidtest if said estimated confidence level is outside said threshold; aninterface associated with said microprocessor to present said test tosaid patient and to receive said answers provided by said patient; and adatabase associated with said processor to store said test, saidplurality of questions, said answers provided by said patient, and saidestimated ailment impact score.
 2. The system of claim 1, wherein saidmicroprocessor provides a list of possible answers for each questionfrom said database to said patient via said interface.
 3. The system ofclaim 1, wherein said microprocessor generates said test to determinethe impact of said ailment on a condition experienced or perceived bysaid patient, said condition being physical, social, role, emotional,and cognitive functioning.
 4. The system of claim 1, wherein saidmicroprocessor generates said test to determine the impact of saidailment on at least one of the following indicators of functional healthand well being: restrict recreational activities, lie down and rest,feel frustrated, difficult to focus attention, restrict performing dailyactivities, feel irritable, limit ability to do activities, difficultyin performing daily activities, keep from enjoying social activities,limit ability to concentrate, keep you from socializing, afraid ofletting others down, avoid social or family activities, place stress onyour relationships, feel like a burden on others, avoid traveling, feeldesperate, cancel work or daily activities, need help in routine dailytasks, and keep you in bed.
 5. The system of claim 1, wherein saidmicroprocessor generates said test to determine the impact of one of thefollowing ailments: headache, hernia, rhinitis, asthma, overweight,osteoarthritis, diabetes, chronic obstructive pulmonary disease,depression, congestive heart failure, and rheumatoid arthritis.
 6. Thesystem of claim 1, wherein said microprocessor is further configured togenerate a report regarding said estimated ailment impact score of saidpatient, and to compare said answers provided by said patient withanswers provided by other patients in said domain stored in saiddatabase.
 7. The system of claim 1, wherein said microprocessor isfurther configured to rank said plurality of questions in accordancewith said estimated ailment impact score, and to select a highest rankedquestion that has not been administered to said patient from saidplurality of questions stored in said database based on said ranking. 8.The system of claim 1, wherein said microprocessor is further configuredto terminate said administration of said test if it is determined thatsaid estimated confidence level is within said threshold.
 9. The systemof claim 1, wherein said microprocessor generates said test having saidplurality of questions to determine the impact of said ailment on aplurality of HRQOL domains.
 10. The system of claim 1, wherein saidmicroprocessor is configured to statistically analyze said answersprovided by said patient for errors, consistency, or estimatingnon-responsive answers to said test.
 11. The system of claim 1, furthercomprising a network and wherein said microprocessor is configured toadminister said customized test to said patient over said network. 12.The system of claim 1, wherein said microprocessor is configured togenerate said standardized common metric of the impact of an ailment onsaid HRQOL domain across a plurality of ailments or age groups.
 13. Thesystem of claim 12, wherein said microprocessor is further configuredto: perform a uni-dimensionality evaluation on a plurality of indicatorsof functional health and well-being impacted by said plurality ofailments to provide a first set of candidate indicators; perform adifferential item functioning analyses on said plurality of indicatorsof functional health and well-being impacted by said plurality ofailments to provide a second set of candidate indicators; build an itembank of said plurality of indicators of functional health and well-beingimpacted by said plurality of ailments from said indicators that aremembers of both said first and second sets of candidate indicators toprovide indicators that are stably scaled across said plurality ofailments or age groups; and order said indicators of functional healthand well-being impacted by said plurality of ailments that are stablyscaled across said plurality of ailments or age groups in accordancewith the relative level of ailment impact defined by each to form saidstandardized common metric of the impact of an ailment on said HRQOLdomain of said at least one patient across said plurality of ailments orage groups.
 14. The system of claim 1, wherein said microprocessor isfurther configured to develop clinical benchmarks for interpretation ofsaid estimated ailment impact score.
 15. A method of assessing theimpact of an ailment on a health related quality of life (HRQOL) domainof a patient, wherein said HRQOL domain comprises a plurality ofindicators of functional health and well being, comprising the steps of:generating a customized test from a database comprising questions for aplurality of HRQOL domains, said test having a plurality of questionsfor said patient to determine the impact of said ailment on said HRQOLdomain by a microprocessor, wherein each question comprises an indicatorof functional health and well being as a result of said ailment, whereinsaid indicator is stably scaled across ailments whose impact is to beassessed to establish a standardized common metric for comparing theimpact of various ailments; administering said test by saidmicroprocessor by providing one question at a time to said patient viaan interface associated with said microprocessor; evaluating by saidmicroprocessor, after each question, answers provided by said patient toestimate an ailment impact score and a confidence level in the accuracyof said estimated ailment impact score; varying a threshold by saidmicroprocessor, after each question, as a function of said estimatedaliment impact score during administration of said test to said patient;storing said test, said answers provided by said patient, and saidestimated ailment impact score in said database; and dynamicallymodifying said test by said microprocessor if said estimated confidencelevel is outside said threshold.
 16. The method of claim 15, furthercomprising the step of providing a list of possible answers for eachquestion by said microprocessor from said database to said patient viasaid interface.
 17. The method of claim 15, further comprising the stepof generating said test by said microprocessor to determine the impactof said ailment on a condition experienced or perceived by said patient,said condition being at least one of the following: physical, social,role, emotional, and cognitive functioning.
 18. The method of claim 15,further comprising the step of generating said test by saidmicroprocessor to determine the impact of said ailment on at least oneof the following indicator of functional health and well being: restrictrecreational activities, lie down and rest, feel frustrated, difficultto focus attention, restrict performing daily activities, feelirritable, limit ability to do activities, difficulty in performingdaily activities, keep from enjoying social activities, limit ability toconcentrate, keep you from socializing, afraid of letting others down,avoid social or family activities, place stress on your relationships,feel like a burden on others, avoid traveling, feel desperate, cancelwork or daily activities, need help in routine daily tasks, and keep youin bed.
 19. The method of claim 15, further comprising the step ofgenerating said test by said microprocessor to determine the impact ofone of the following ailments on said patient: headache, hernia,rhinitis, asthma, overweight, osteoarthritis, diabetes, chronicobstructive pulmonary disease, depression, congestive heart failure, andrheumatoid arthritis.
 20. The method of claim 15, further comprising thesteps of generating by said microprocessor a report regarding saidestimated ailment impact score of said patient and comparing by saidmicroprocessor said answers provided by said patient with answersprovided by other patients in said domain stored in said database. 21.The method of claim 15, further comprising the steps of ranking saidplurality of questions by said microprocessor in accordance with saidestimated ailment impact score; selecting a higher ranked question bysaid microprocessor that has not been administered to said patient fromsaid plurality of questions stored in said database based on saidranking.
 22. The method of claim 15, further comprising the step ofterminating said administration of said test by said microprocessor ifit is determined that said estimated confidence level is within saidthreshold.
 23. The method of claim 15, further comprising the step ofgenerating by said microprocessor said test having said plurality ofquestions to determine the impact of said ailment on a plurality ofHRQOL domains.
 24. The method of claim 15, further comprising the stepof statistically analyzing by said microprocessor said answers providedby said patient for errors, consistency, or estimating non-responsiveanswers to said test.
 25. The method of claim 22, further comprising thestep of administering by said microprocessor said test to said patientsover a network.
 26. The method of claim 15, further comprising the stepof generating by said microprocessor said standardized common metric ofthe impact of an ailment on said HRQOL domain across a plurality ofailments or age groups.
 27. The method of claim 15, further comprisingthe steps of: performing by said microprocessor a uni-dimensionalityevaluation on a plurality of indicators of functional health andwell-being impacted by said plurality of ailments to provide a first setof candidate indicators; performing by said microprocessor adifferential item functioning analyses on said plurality of indicatorsof functional health and well-being impacted by said plurality ofailments to provide a second set of candidate indicators; building bysaid microprocessor an item bank of said plurality of indicators offunctional health and well-being impacted by said plurality of ailmentsfrom said indicators that are members of both said first and second setsof candidate indicators to provide indicators that are stably scaledacross said plurality of ailments or age groups; and ordering by saidmicroprocessor said indicators of functional health and well-beingimpacted by said plurality of ailments that are stably scaled acrosssaid plurality of ailments or age groups in accordance with the relativelevel of ailment impact defined by each to form said standardized commonmetric of the impact of an ailment on said HRQOL domain of said at leastone patient across said plurality of ailments or age groups.
 28. Themethod of claim 15, further comprising the step of developing by saidmicroprocessor clinical benchmarks for interpretation of said estimatedailment impact score.
 29. A computer readable medium comprising code forassessing the impact of an ailment on a health related quality of life(HRQOL) domain of a patient, wherein said HRQOL domain comprises aplurality of indicators of functional health and well being, said codecomprising computer executable instructions for: generating a customizedtest having a plurality of questions for said patient to determine theimpact of said ailment on said HRQOL domain, wherein each questioncomprises an indicator of functional health and well being as a resultof said ailment, wherein said indicator is stably scaled across ailmentswhose impact is to be assessed to establish a standardized common metricfor comparing the impact of various ailments; administering said test byproviding one question at a time to said patient; evaluating, after eachquestion, answers provided by said patient to estimate an ailment impactscore and a confidence level in the accuracy of said estimated ailmentimpact score; varying a threshold, after each question, as a function ofsaid estimated aliment impact score during administration of said testto said patient; storing said test, said answers provided by saidpatient, and said estimated ailment impact score in a database; anddynamically modifying said test said estimated confidence level isoutside said threshold.
 30. The computer readable medium of claim 29,further comprising computer executable instructions for terminating saidadministration of said test if it is determined that said estimatedconfidence level is within said threshold.
 31. The computer readablemedium of claim 29, further comprising computer executable instructionsfor statistically analyzing said answers provided by said patient forerrors, consistency, or estimating non-responsive answers to said test.